diff --git a/examples/trace.rs b/examples/trace.rs
new file mode 100644
index 0000000..40fa733
--- /dev/null
+++ b/examples/trace.rs
@@ -0,0 +1,70 @@
+use std::sync::Arc;
+
+use radn::{
+    flow::{comparator::*, traversible::algorithms::subset::*},
+    func::*,
+    mrds::trees::unbalanced::*,
+    rstd::tracing::*,
+};
+use rand::{Rng, SeedableRng};
+
+type TracedMonad = instances::composition::CompositionInstance<
+    TracedInstance,
+    instances::result::ResultInstance<()>,
+>;
+
+trait FromSlice<R> {
+    type Tree;
+    type A;
+
+    fn from_slice(self: &Arc<Self>, rng: &mut R, slice: &[Self::A]) -> Arc<Self::Tree>;
+}
+
+impl<'a, T: Monad<'a>, A: 'a + Send + Sync + Clone, R: 'a + rand::Rng> FromSlice<R>
+    for UnbalancedConstructor<'a, T, A>
+{
+    type A = A;
+    type Tree = UnbalancedTree<'a, T, A>;
+
+    fn from_slice(self: &Arc<Self>, rng: &mut R, slice: &[Self::A]) -> Arc<Self::Tree> {
+        if slice.is_empty() {
+            self.leaf()
+        } else {
+            let key_at = rng.gen_range(0..slice.len());
+            let key = slice[key_at].clone();
+            let lslice = &slice[..key_at];
+            let rslice = &slice[key_at + 1..];
+            self.clone().node(
+                self.clone().from_slice(rng, lslice),
+                key,
+                self.clone().from_slice(rng, rslice),
+            )
+        }
+    }
+}
+
+fn main() {
+    let ctr: Arc<UnbalancedConstructor<TracedMonad, _>> =
+        UnbalancedConstructor::rc(Box::new(|node| {
+            Box::new(move || TracedMonad::pure(node.clone()).after_resolution())
+        }));
+    let mut rng = rand::rngs::StdRng::seed_from_u64(426);
+    let big: Vec<i32> = (0..(rng.gen_range(1000..2000))).collect();
+    let key = big[rng.gen_range(0..big.len())];
+    let small: Vec<i32> = big
+        .iter()
+        .filter(|x| **x != key && rng.gen_ratio(4, 5))
+        .copied()
+        .collect();
+    let t_small = ctr.from_slice(&mut rng, &small);
+    let t_big = ctr.from_slice(&mut rng, &big);
+    let traced = t_subset_of_t(
+        &DefaultComparator,
+        t_small.clone(),
+        t_big.clone(),
+        None,
+        None,
+    );
+    assert!(traced.value.is_ok());
+    println!("{:?}", traced.render().to_vec());
+}