diff --git a/src/bin/flat/riemann.rs b/src/bin/flat/riemann.rs
index afc4b7b..ef07959 100644
--- a/src/bin/flat/riemann.rs
+++ b/src/bin/flat/riemann.rs
@@ -62,7 +62,6 @@ pub struct TraceIter<'a, M: Metric> {
 	space: &'a M,
 	p: Vec2,
 	v: Vec2,
-	dt: f32,
 }
 
 impl<'a, M: Metric> Iterator for TraceIter<'a, M> {
@@ -70,8 +69,8 @@ impl<'a, M: Metric> Iterator for TraceIter<'a, M> {
 
 	fn next(&mut self) -> Option<Self::Item> {
 		let a: Vec2 = -contract2(krist(self.space, self.p), self.v);
-		self.v = self.v + a * self.dt;
-		self.p = self.p + self.v * self.dt;
+		self.v += a;
+		self.p += self.v;
 		Some(self.p)
 	}
 }
@@ -80,8 +79,7 @@ pub fn trace_iter<M: Metric>(space: &M, base: Vec2, dir: Vec2, dt: f32) -> Trace
 	TraceIter {
 		space,
 		p: base,
-		v: space.normalize_vec_at(base, dir),
-		dt,
+		v: dt * space.normalize_vec_at(base, dir),
 	}
 }