diff --git a/Cargo.lock b/Cargo.lock
index c337d7f..3679354 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -162,6 +162,7 @@ dependencies = [
  "serde_cbor",
  "smallvec",
  "tokio",
+ "treemap",
 ]
 
 [[package]]
@@ -781,6 +782,12 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "treemap"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1571f89da27a5e1aa83304ee1ab9519ea8c6432b4c8903aaaa6c9a9eecb6f36"
+
 [[package]]
 name = "unicode-segmentation"
 version = "1.7.1"
diff --git a/Cargo.toml b/Cargo.toml
index 13ab3bd..d7f3df9 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,7 +13,7 @@ codegen-units = 1
 panic = "unwind"
 
 [features]
-default = ["splash", "inspect", "defer-drop", "jemalloc", "prealloc"]
+default = ["splash", "inspect", "defer-drop", "jemalloc", "prealloc", "treemap"]
 
 # When using the REPL to inspect graphs, save command history.
 save-history = []
@@ -52,3 +52,4 @@ serde = {version = "1.0.123", features=["derive"], optional=true}
 serde_cbor = {version = "0.11.1", optional=true}
 smallvec = "1.6.1"
 tokio = {version = "0.2", features=["full"]}
+treemap = {version = "0.3.2", optional=true}
diff --git a/src/arg/parsing.rs b/src/arg/parsing.rs
index 1c802f2..ef218de 100644
--- a/src/arg/parsing.rs
+++ b/src/arg/parsing.rs
@@ -6,6 +6,33 @@ use std::fmt;
 
 #[cfg(feature="inspect")] use config::OutputSerialisationMode;
 
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub enum InspectKind
+{
+    Treemap(Option<(u64, u64)>),
+}
+
+impl fmt::Display for InspectKind
+{
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
+    {
+	match self {
+	    Self::Treemap(None) => write!(f, "treemap"),
+	    Self::Treemap(Some((x,y))) => write!(f, "treemap:{}:{}", x, y), // Width and height.
+	}
+    }
+}
+
+impl std::str::FromStr for InspectKind
+{
+    type Err = eyre::Report;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err>
+    {
+	todo!()
+    }
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum Argument
 {
@@ -29,6 +56,8 @@ pub enum Argument
 
     StopReading,
 
+    Inspect(InspectKind),
+
     Input(String),
 }
 
@@ -70,6 +99,9 @@ impl Argument
     {
 	use Argument::*;
 	match self {
+	    Inspect(InspectKind::Treemap(None)) => cfg.inspection.treemap = Some((640, 480)),
+	    Inspect(InspectKind::Treemap(x)) => cfg.inspection.treemap = x,
+	    
 	    LimitConcMaxProc => cfg.max_tasks = config::max_tasks_cpus(),
 	    LimitConc(max) => cfg.max_tasks = Some(max),
 	    UnlimitConc => cfg.max_tasks = None,
@@ -108,6 +140,8 @@ impl fmt::Display for Argument
 	use Argument::*;
 	match self
 	{
+	    Inspect(ins) => write!(f, "--inspect {}", ins),
+	    
 	    ModeChangeHelp => write!(f, "--help"),
 	    LimitConcMaxProc => write!(f, "-m"),
 	    LimitConc(limit) => write!(f, "--threads {}", limit),
@@ -365,7 +399,12 @@ where I: Iterator<Item=String>
     let mut keep_reading = Continue::Yes;
     let item = match this.trim()
     {
-	"--threads" => {
+	"--inspect" => {
+	    let ins = args.next().ok_or(eyre!("`--inspect` expects a parameter"))
+		.with_suggestion(suggestion_intended_arg.clone())?;
+	    Argument::Inspect(ins.parse().wrap_err(eyre!("Failed to parse parameter for `--inspect`"))?)
+	},
+	" --threads" => {
 	    let max = args.next().ok_or(eyre!("`--threads` expects a parameter"))
 		.with_suggestion(suggestion_intended_arg.clone())?;
 	    match NonZeroUsize::new(max.parse::<usize>()
diff --git a/src/config.rs b/src/config.rs
index 98f2fb8..b8fbd4c 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -121,6 +121,25 @@ impl OutputSerialisationMode
     }
 }
 
+/// What to do with the graph afterwards?
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Inspection
+{
+    pub treemap: Option<(u64, u64)>, //w and h
+}
+
+impl Default for Inspection
+{
+    #[inline]
+    fn default() -> Self
+    {
+	Self {
+	    treemap: None
+	}
+    }
+}
+
+
 /// Configuration for this run
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Config
@@ -133,6 +152,8 @@ pub struct Config
     
     #[cfg(feature="inspect")]
     pub serialise_output: Option<OutputSerialisationMode>,
+
+    pub inspection: Inspection,
 }
 
 impl Config
@@ -188,6 +209,8 @@ impl Default for Config
 	    output_level: Default::default(),
 	    #[cfg(feature="inspect")]
 	    serialise_output: None,
+
+	    inspection: Default::default(),
 	}
     }
 }
diff --git a/src/data/graph.rs b/src/data/graph.rs
index e2dc052..102ff46 100644
--- a/src/data/graph.rs
+++ b/src/data/graph.rs
@@ -15,8 +15,123 @@ pub struct INodeInfoGraph
     children: HashMap<INode, Vec<INode>>, //reverse lookup for directory INodes and their parent INodes
 }
 
+#[derive(Debug, Clone)]
+pub struct INodeInfoGraphEntry<'a>
+{
+    master: &'a INodeInfoGraph,
+    inode: INode,
+}
+
+impl<'a> INodeInfoGraphEntry<'a>
+{
+    /// Create an iterator over children of this graph item.
+    ///
+    /// # Note
+    /// Returns `None` if this is not a directory item.
+    pub fn level(&self) -> Option<Level<'a>>
+    {
+	match self.master.inodes.get(&self.inode)
+	{
+	    Some(FsInfo::Directory(parent)) => {
+		Some(
+		    Level{
+			master: self.master,
+			inode: self.inode.clone(),
+			children: match self.master.children.get(&self.inode) {
+			    Some(iter) => iter.iter(),
+			    _ => [].iter(),
+			},
+		    }
+		)
+	    },
+	    Some(FsInfo::File(_, _)) => None,
+	    None => {
+		panic!("No lookup information for inode {:?}", self.inode)
+	    }//Some(Level{master: self.master, inode: None, children: [].iter()}),
+	}
+    }
+
+    /// The `FsInfo` for this item.
+    pub fn info(&self) -> &FsInfo
+    {
+	self.master.inodes.get(&self.inode).unwrap()
+    }
+    /// The path for this inode
+    pub fn path(&self) -> &PathBuf
+    {
+	self.master.paths_reverse.get(&self.inode).unwrap()
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Level<'a>
+{
+    master: &'a INodeInfoGraph,
+    inode: INode,// Should only ever be `Directory` for `Level`.
+    children: std::slice::Iter<'a, INode>,
+}
+
+#[derive(Debug, Clone)]
+pub struct TopLevel<'a>
+{
+    master: &'a INodeInfoGraph,
+    children: std::vec::IntoIter<&'a INode>,
+}
+
+impl<'a> Iterator for TopLevel<'a>
+{
+    type Item = INodeInfoGraphEntry<'a>;
+    fn next(&mut self) -> Option<Self::Item>
+    {
+	let master = self.master;
+	self.children.next().map(|inode| {
+	    INodeInfoGraphEntry{
+		master,
+		inode: inode.clone(),
+	    }
+	})
+    }
+}
+
+
+impl<'a> Iterator for Level<'a>
+{
+    type Item = INodeInfoGraphEntry<'a>;
+    fn next(&mut self) -> Option<Self::Item>
+    {
+	let master = self.master;
+	self.children.next().map(|inode| {
+	    INodeInfoGraphEntry{
+		master,
+		inode: inode.clone(),
+	    }
+	})
+    }
+}
+
 impl INodeInfoGraph
 {
+    /// Total size of all files
+    pub fn total_size(&self) -> u64
+    {
+	self.inodes.iter().map(|(_, v)| {
+	    match v {
+		FsInfo::File(len, _) => *len,
+		_ => 0,
+	    }
+	}).sum()
+    }
+    /// An iterator over the top level of items
+    pub fn top_level(&self) -> TopLevel<'_>
+    {
+	let top_level = self.inodes.iter().filter(|(node, _)| {
+	    !self.inodes.contains_key(node)
+	});
+	TopLevel {
+	    master: self,
+	    children: top_level.map(|(k, _)| k).collect::<Vec<_>>().into_iter(),
+	}
+    }
     /// Create a new graph from these linked `HashMap`s
     #[inline] pub fn new(inodes: HashMap<INode, FsInfo>, paths: HashMap<PathBuf, INode>) -> Self
     {
@@ -48,6 +163,11 @@ impl INodeInfoGraph
 	self.paths_reverse.extend(self.paths.iter().map(|(x,y)| (*y,x.clone())));
 	self
     }
+    /// Total number of items in the graph
+    #[inline] pub fn len(&self) -> usize
+    {
+	self.children.len()
+    }
     /// Get the FsInfo of this `INode`
     #[inline] pub fn get_info(&self, node: impl Borrow<INode>) -> Option<&FsInfo>
     {
@@ -57,17 +177,17 @@ impl INodeInfoGraph
     /// An iterator over top-level children of this node
     pub fn children_of(&self, node: impl Borrow<INode>) -> !//Children<'_>
     {
-	todo!();
-	/*Children(self, match self.children.get(node.borrow()) {
-	Some(slc) => slc.iter(),
-	_ => [].iter(),
-    })*/
-    }
+    todo!();
+    /*Children(self, match self.children.get(node.borrow()) {
+    Some(slc) => slc.iter(),
+    _ => [].iter(),
+})*/
+}
     /// An iterator over all the directories in this 
     pub fn directories(&self) -> !//Directories<'_>
     {
-	todo!()//Directories(self, self.children.keys())
-    }*/
+    todo!()//Directories(self, self.children.keys())
+}*/
 
     /// Convert into a hierarchical representation
     pub fn into_hierarchical(self) -> HierarchicalINodeGraph
@@ -264,6 +384,12 @@ impl HierarchicalINodeGraph
 	    hi.len().map(|x| (path.as_path(), x))
 	}).max_by_key(|x| x.1)
     }
+
+    /// Complete number of items in the tree
+    #[inline] pub fn len(&self) -> usize
+    {
+	self.table.len()
+    }
 }
 
 impl From<INodeInfoGraph> for HierarchicalINodeGraph
diff --git a/src/data/mod.rs b/src/data/mod.rs
index 8aabf34..8b493e4 100644
--- a/src/data/mod.rs
+++ b/src/data/mod.rs
@@ -18,6 +18,7 @@ pub use graph::{
     INodeInfoGraph,
     HierarchicalINodeGraph,
     FsObjKind as FsKind,
+    INodeInfoGraphEntry,
 };
 
 /// A raw file or directory inode number
diff --git a/src/ext.rs b/src/ext.rs
index 90ab111..b301295 100644
--- a/src/ext.rs
+++ b/src/ext.rs
@@ -238,11 +238,11 @@ impl<I: Iterator> Iterator for OptionIterator<I>
     type Item = I::Item;
     fn next(&mut self) -> Option<Self::Item>
     {
-	self.0.map(|x| x.next()).flatten()
+	self.0.as_mut().map(|x| x.next()).flatten()
     }
 
     fn size_hint(&self) -> (usize, Option<usize>) {
-	match self.0 {
+	match self.0.as_ref() {
 	    Some(i) => i.size_hint(),
 	    _ => (0, Some(0)),
 	}
@@ -257,7 +257,7 @@ impl<I: Iterator> DoubleEndedIterator for OptionIterator<I>
 where I: DoubleEndedIterator
 {
     fn next_back(&mut self) -> Option<Self::Item> {
-	self.0.map(|x| x.next_back()).flatten()
+	self.0.as_mut().map(|x| x.next_back()).flatten()
     }
 }
 
diff --git a/src/info/map.rs b/src/info/map.rs
new file mode 100644
index 0000000..a9398c2
--- /dev/null
+++ b/src/info/map.rs
@@ -0,0 +1,124 @@
+use super::*;
+use treemap::{
+    Rect,
+    Mappable,
+    TreemapLayout
+};
+use data::{FsInfo, INodeInfoGraph, INodeInfoGraphEntry};
+
+/// A treemap of all **files** in the graph.
+#[derive(Debug, Clone, PartialEq)]
+pub struct Treemap
+{
+    //layout: TreemapLayout,
+    nodes: Vec<MapNode>,
+}
+
+impl Treemap
+{
+    /// All nodes of the map.
+    #[inline] pub fn nodes(&self) -> &[MapNode]
+    {
+	&self.nodes[..]
+    }
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct MapNode
+{
+    name: String,
+    
+    vw_size: f64, // Should be halved each iteration
+    vw_bounds: Rect, // should be Rect::new() before aligntment
+}
+
+impl MapNode
+{
+    /// The calculated bounds of the node
+    #[inline] pub fn bounds(&self) -> &Rect
+    {
+	&self.vw_bounds
+    }
+    /// The name of the node
+    #[inline] pub fn name(&self) -> &str
+    {
+	&self.name[..]
+    }
+    
+    #[inline] fn size(&self) -> f64 //Is this useful for consumer?
+    {
+	self.vw_size
+    }
+    
+    #[inline] fn new(name: String) -> Self
+    {
+	Self {
+	    vw_size: 1.0,
+	    vw_bounds: Rect::new(),
+	    name,
+	}
+    }
+}
+
+/// Create a treemap from this graph.
+pub fn treemap(_cfg: &Config, graph: &INodeInfoGraph, (w, h): (f64, f64)) -> Treemap
+{
+    let layout = TreemapLayout::new();
+    let mut nodes = Vec::with_capacity(graph.len());
+    //TODO: Recursively walk the graph, halving size with each iteration. (Maybe we need `INodeInfoGraph` here, not `Hierarchicalinodegraph`?)
+    let total_size = graph.total_size();
+
+    let size = 1.0;
+
+    fn calc_path<'a, I: IntoIterator<Item = INodeInfoGraphEntry<'a>>>(insert: &'a mut Vec<MapNode>, from: I, total_size: u64, size: f64, scale: f64)
+    {
+	for top in from {
+	    let path = top.path();
+	    match top.info() {
+		FsInfo::Directory(_) => {
+		    //TODO: Do we add dir itself? I think not?
+		    // Add children
+		    let size = size * 0.5;
+		    calc_path(insert, top.level().unwrap(), total_size, size, scale);
+		},
+		&FsInfo::File(sz, _) => {
+		    let fract = (sz as f64) / (total_size as f64);
+		    insert.push(MapNode {
+			name: path.to_string_lossy().into_owned(),
+			vw_size: fract * scale,
+			vw_bounds: Rect::new(),
+		    })
+		},
+	    }
+	}
+    }
+    
+    calc_path(&mut nodes, graph.top_level(), total_size, size, 1.0);
+
+    layout.layout_items(&mut nodes[..], Rect {
+	x: 0.0,
+	y: 0.0,
+	w, h,
+    });
+    
+    Treemap {
+	//layout,
+	nodes
+    }
+}
+
+impl Mappable for MapNode
+{
+    fn size(&self) -> f64
+    {
+	self.vw_size
+    }
+    fn bounds(&self) -> &Rect
+    {
+	&self.vw_bounds
+    }
+    fn set_bounds(&mut self, bounds: Rect)
+    {
+	self.vw_bounds = bounds;
+    }
+}
diff --git a/src/info/mod.rs b/src/info/mod.rs
index 27087a7..2a8b571 100644
--- a/src/info/mod.rs
+++ b/src/info/mod.rs
@@ -4,7 +4,7 @@ use super::*;
 use data::HierarchicalINodeGraph;
 use config::Config;
 
-pub mod repl;
+//pub mod repl;
 
 /// Print the most basic info
 pub fn print_basic_max_info(cfg: &Config, graph: &HierarchicalINodeGraph)
@@ -13,3 +13,9 @@ pub fn print_basic_max_info(cfg: &Config, graph: &HierarchicalINodeGraph)
     cfg_println!(Quiet; cfg, "Max size dir: {:?}", graph.path_max_size_for(data::FsKind::Directory));
     cfg_println!(Quiet; cfg, "Max size all: {:?}", graph.path_max_size());
 }
+
+
+#[cfg(feature="treemap")]
+mod map;
+#[cfg(feature="treemap")]
+pub use map::*;
diff --git a/src/main.rs b/src/main.rs
index f264790..5715956 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -99,7 +99,7 @@ async fn write_graph(graph: Arc<data::HierarchicalINodeGraph>) -> eyre::Result<(
 		.wrap_err(eyre!("Failed to open file for mapping"))
 		.with_section(|| format!("{:?}", output_file).header("File was"))?;
 	    let mut file = file.into_std().await;
-        cfg_eprintln!(Verbose; cfg, "Opened file for prealloc-write");
+            cfg_eprintln!(Verbose; cfg, "Opened file for prealloc-write");
 	    tokio::task::spawn_blocking(move || {
 		serial::write_sync_map(&mut file, graph.as_ref())
 	    }).await.wrap_err(eyre!("Prealloc panicked while dumping"))
@@ -127,13 +127,31 @@ async fn normal(cfg: config::Config) -> eyre::Result<()>
     };
     
     let cfg = cfg.make_global();
-    let graph = tokio::task::spawn_blocking(move || {
+    let (treemap, graph) = tokio::task::spawn_blocking(move || {
 	cfg_println!(Verbose; cfg, "Computing hierarchy...");
+
+	// Create treemap
+	#[cfg(feature="treemap")] 
+	let treemap = {
+	    //Check config for if the treemap flag is present. If it is, get the width and height from there too.
+	    if let Some(&(x,y)) = cfg.inspection.treemap.as_ref() {
+		Some(info::treemap(cfg, &graph, (
+		    x as f64,
+		    y as f64,
+		)))
+	    } else {
+		None
+	    }
+	};
+	#[cfg(not(feature="treemap"))]
+	let treemap = Option::<std::convert::Infallible>::None;
+
+	// Create recursive graph
 	let mut graph = graph.into_hierarchical();
 	cfg_println!(Verbose; cfg, "Computing sizes...");
 
 	graph.compute_recursive_sizes();
-	graph
+	(treemap, graph)
     }).await.expect("Failed to compute hierarchy from graph");
 
     //#[cfg(debug_assertions)] cfg_eprintln!(Verbose; cfg, "{:?}", graph);
@@ -155,6 +173,12 @@ async fn normal(cfg: config::Config) -> eyre::Result<()>
 	}
     };
 
+    #[cfg(feature="treemap")] 
+    if let Some(treemap) = treemap {
+	//TODO: Print treemap
+	todo!("{:?}",treemap);
+    }
+    
     info::print_basic_max_info(&cfg, &graph);
 
     #[cfg(feature="inspect")]