diff --git a/src/main.rs b/src/main.rs
index 424328f..88a0a9a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -18,7 +18,7 @@ mod relation;
 
 fn main() {
     use entity::{Point, PointRef, Var};
-    use math::{Point2, eqn, Region2};
+    use math::{Point2, eqn, Region2, Rot2};
     use relation::{Relation, ResolveResult};
 
     env_logger::init();
@@ -48,8 +48,9 @@ fn main() {
     let c4 = relation::PointAngle::new_vertical(p1.clone(), p2.clone());
     let c3 = relation::PointAngle::new_horizontal(p2.clone(), p3.clone());
     let c2 = relation::AlignedDistance::new_vertical(p1.clone(), p2.clone(), 12.);
+    let c5 = relation::PointAngle::new(p1.clone(), p3.clone(), Rot2::from_angle_deg(45.));
     let mut relations: Vec<Box<dyn Relation>> =
-        vec![/*Box::new(c1),*/ Box::new(c2), Box::new(c3), Box::new(c4)];
+        vec![/*Box::new(c1),*/ Box::new(c2), Box::new(c3), Box::new(c4), Box::new(c5)];
     let mut constrained: Vec<Box<dyn Relation>> = Vec::new();
     let mut any_underconstrained = true;
     let mut any_constrained = true;
diff --git a/src/math/eqn.rs b/src/math/eqn.rs
index b07fa11..55090b6 100644
--- a/src/math/eqn.rs
+++ b/src/math/eqn.rs
@@ -199,6 +199,9 @@ fn distribute_product_sums(mut es: Exprs) -> Expr {
     trace!("distribute_product_sums: {}", Product(es.clone()));
     use itertools::Itertools;
     use Expr::*;
+    for e in &mut es {
+        *e = e.clone().distribute();
+    }
     let sums = es
         .drain_filter(|e| match e {
             Sum(_) => true,
@@ -383,6 +386,10 @@ impl Expr {
                 match v {
                     box Const(c) => Const(-c),
                     box Neg(v) => *v,
+                    box Product(mut es) => {
+                        es.push(Const(-1.));
+                        Product(es)
+                    }
                     e => Product(vec![Const(-1.), *e]),
                 }
             }
diff --git a/src/math/mod.rs b/src/math/mod.rs
index 44c6945..e51e087 100644
--- a/src/math/mod.rs
+++ b/src/math/mod.rs
@@ -212,6 +212,7 @@ impl Line2 {
             + b_0.y.clone() * a_c.clone())
             / (a_s.clone() * b_c.clone() - a_c.clone() * b_s.clone());
         // Region2::Singleton(b.evaluate(t_b))
+        trace!("intersect a: {}, b: {}, t_b = {}", a, b, t_b);
         let res = Region2::Line(b.clone().with_extent(Region1::Singleton(t_b.simplify())));
         trace!("intersect a: {}, b: {} = {}", a, b, res);
         res
diff --git a/src/math/vec.rs b/src/math/vec.rs
index 6890405..753b948 100644
--- a/src/math/vec.rs
+++ b/src/math/vec.rs
@@ -92,8 +92,8 @@ impl<T> Point2<T> {
 impl Point2<Value> {
   pub fn simplify(self) -> Self {
     Self {
-      x: self.x.simplify(),
-      y: self.y.simplify(),
+      x: self.x.distribute().simplify().distribute().simplify(),
+      y: self.y.distribute().simplify().distribute().simplify(),
     }
   }
 }
@@ -170,6 +170,10 @@ impl Rot2 {
     }
   }
 
+  pub fn from_angle_deg(angle_deg: Scalar) -> Self {
+    Self::from_angle(angle_deg * std::f64::consts::PI / 180.)
+  }
+
   pub fn cardinal(index: i64) -> Self {
     match index % 4 {
       0 => Rot2 {