diff --git a/TODO.md b/TODO.md
index 85c51f0..c08c6db 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,2 +1,4 @@
-TODO: Support -R - Non-blind recursion (like sxiv-ordered)
-NOTE: Nesting BTreeSet is probably not the best way to go about this...
+# TODO: Support -R - Non-blind recursion (like sxiv-ordered)
+
+## Requires
+A mpsc channel refactor to support sending parents...
diff --git a/src/main.rs b/src/main.rs
index ae4c13d..dce7949 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -46,6 +46,20 @@ async fn work_on(cfg: work::Config, mut into: mpsc::Receiver<work::FileInfo>) ->
     Ok(map)
 }
 
+async fn work_on_tree(cfg: work::Config, mut into: mpsc::Receiver<(Option<work::FileInfo>, work::FileInfo)>) -> eyre::Result<work::NestedFsTreeMap>
+{
+    //TODO: How to refactor the mpsc channel to support this and the blind (above) version???
+    use work::*;
+    let mut map = NestedFsTreeMap::new(cfg);
+    while let Some((parent, file)) = into.recv().await {
+	if cfg!(debug_assertions) {
+	    trace!("insert {:?}/ +{}", parent, map.len());
+	}
+	map.insert(parent, file);
+    }
+    Ok(map)
+}
+
 async fn walk_paths<I, P>(paths: I, cfg: walk::Config, worker_cfg: &std::sync::Arc<work::Config>, to: mpsc::Sender<work::FileInfo>) -> eyre::Result<usize>
 where I: futures::stream::Stream<Item = P>,
       P: AsRef<std::path::Path>
diff --git a/src/work.rs b/src/work.rs
index aee3f50..b5a120b 100644
--- a/src/work.rs
+++ b/src/work.rs
@@ -33,6 +33,7 @@ pub struct FileInfo
     state: Arc<Config>, //TODO: XXX: This will be a *severe* slowdown... How can we have just a reference here? Thread local? `tokio::task_local!`? Global static?
     path: PathBuf,
     meta: Metadata,
+    dir: bool,
 }
 
 impl FileInfo
@@ -53,6 +54,7 @@ impl FileInfo
     {
 	Self {
 	    state: config.into(),
+	    dir: meta.is_dir(),
 	    path, meta
 	}
     }
@@ -122,6 +124,46 @@ impl order::Orderer<FileInfo> for FileInfo
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Default)]
 pub struct FSTimeMap(Arc<Config>, BTreeSet<order::Ordered<FileInfo, FileInfo>>);
 
+/// Maps files based on their time maintaining directory structure.
+///
+/// # Note
+/// The output of this ordering is still a flat-map. Children are corrently grouped beneath their parents.
+#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Default)]
+pub struct NestedFsTreeMap(Arc<Config>, BTreeSet<order::Ordered<NestedFileInfo, FileInfo>>);
+
+impl NestedFsTreeMap
+{
+    #[inline] 
+    pub fn new(config: impl Into<Config>) -> Self
+    {
+	Self (Arc::new(config.into()), BTreeSet::new())
+    }
+    
+    #[inline] 
+    pub fn iter(&self) -> impl Iterator<Item = &'_ FileInfo> + ExactSizeIterator + DoubleEndedIterator + std::iter::FusedIterator + '_
+    {
+	self.1.iter().map(|x| &x.inner().file)
+    }
+
+    #[inline] 
+    pub fn into_iter(self) -> impl Iterator<Item = FileInfo> + ExactSizeIterator + DoubleEndedIterator + std::iter::FusedIterator + 'static
+    {
+	self.1.into_iter().map(|x| x.into_inner().file)
+    }
+
+    #[inline] 
+    pub fn insert(&mut self, parent: impl Into<Option<FileInfo>>, file: FileInfo)
+    {
+	self.1.insert(order::Ordered::new(NestedFileInfo::new(parent.into(), file)));
+    }
+
+    #[inline] 
+    pub fn len(&self) -> usize
+    {
+	self.1.len()
+    }
+}
+
 impl FSTimeMap
 {
     #[inline] 
@@ -154,3 +196,72 @@ impl FSTimeMap
 	self.1.len()
     }
 }
+
+/// Tree-maintaining file info
+#[derive(Debug, Clone)]
+pub struct NestedFileInfo
+{
+    file: FileInfo,
+    parent: Option<FileInfo>
+}
+
+impl NestedFileInfo
+{
+    #[inline] 
+    pub fn new(parent: Option<FileInfo>, file: FileInfo) -> Self
+    {
+	Self {
+	    file,
+	    parent,
+	}
+    }
+
+    #[inline] 
+    pub fn into_inner(self) -> FileInfo
+    {
+	self.file
+    }
+
+    #[inline] 
+    pub fn parent(&self) -> Option<&FileInfo>
+    {
+	self.parent.as_ref()
+    }
+}
+
+impl order::Orderer<NestedFileInfo> for FileInfo
+{
+    #[inline] 
+    fn order(a: &NestedFileInfo, b: &NestedFileInfo) -> std::cmp::Ordering {
+	
+	if let Some(parent) = &a.parent {
+	    // Check if `b` is parent of `a`, if so, `a` *always* comes after `b`
+	    if parent.path() == b.file.path() {
+		return std::cmp::Ordering::Greater;
+	    }
+
+	    // If `a`'s parent is not the same as `b`'s parent, then `a` always comes *before* `b`.
+	    if let Some(bparent) = &b.parent {
+		if !FileInfo::order(parent, bparent).is_eq() {
+		    return std::cmp::Ordering::Less;
+		}
+	    }
+	}
+	
+	if let Some(parent) = &b.parent {
+	    // Check if `a` is parent of `b`, if so, `b` *always* comes after `a`.
+	    if parent.path() == a.file.path() {
+		return std::cmp::Ordering::Less;
+	    }
+
+	    // If `b`'s parent is not the same as `a`'s parent, then `b` always comes *before* `a`.
+	    if let Some(aparent) = &a.parent {
+		if !FileInfo::order(parent, aparent).is_eq() {
+		    return std::cmp::Ordering::Greater;
+		}
+	    }
+	}
+
+	FileInfo::order(&a.file, &b.file)
+    }
+}