diff --git a/game/ai.go b/game/ai.go
index 6f7a045..77070f6 100644
--- a/game/ai.go
+++ b/game/ai.go
@@ -3,7 +3,7 @@ package game
 func chooseCommand(s State, teamID int) command {
 	t := s.Teams[teamID]
 	h := t.BatonHolder()
-	if collide(h.Pos+1, h.Lane, s) {
+	if collide(h.Pos+1, h.Lane, s) != nil {
 		if h.Lane <= t.Lane && h.Lane < NumLanes-1 {
 			return left
 		}
diff --git a/game/physics.go b/game/physics.go
index f95a752..b775a9c 100644
--- a/game/physics.go
+++ b/game/physics.go
@@ -1,5 +1,7 @@
 package game
 
+import "log"
+
 func accelerate(b Bot) Bot {
 	if b.a < -maxA {
 		b.a = -maxA
@@ -21,7 +23,9 @@ func accelerate(b Bot) Bot {
 
 func moveBot(s State, teamID int, b Bot) State {
 	for i := 0; i < b.v; i++ {
-		if !collide(b.Pos+1, b.Lane, s) {
+		if o := collide(b.Pos+1, b.Lane, s); o != nil {
+			log.Printf("bot %d crashed into %#v!", b.ID, o)
+		} else {
 			b.Pos++
 		}
 	}
@@ -30,20 +34,20 @@ func moveBot(s State, teamID int, b Bot) State {
 	return s
 }
 
-func collide(pos, lane int, s State) bool {
+func collide(pos, lane int, s State) interface{} {
 	for _, o := range s.Obstacles {
 		if o.Pos == pos && o.Lane == lane {
-			return true
+			return o
 		}
 	}
 	for _, t := range s.Teams {
 		for _, b := range t.Bots {
 			if b.Pos == pos && b.Lane == lane {
-				return true
+				return b
 			}
 		}
 	}
-	return false
+	return nil
 }
 
 const (
diff --git a/gfx/gfx.go b/gfx/gfx.go
index ee60c96..c9b537a 100644
--- a/gfx/gfx.go
+++ b/gfx/gfx.go
@@ -3,7 +3,6 @@ package gfx
 import (
 	"image/color"
 	"relay/game"
-	"time"
 
 	"github.com/faiface/pixel"
 	"github.com/faiface/pixel/imdraw"
@@ -17,13 +16,13 @@ type RenderState struct {
 	Frame     int
 }
 
-func Render(rs RenderState, sOld, sNew game.State, w *pixelgl.Window, d time.Duration) RenderState {
+func Render(rs RenderState, sOld, sNew game.State, w *pixelgl.Window) RenderState {
 	w.Clear(colornames.Peru)
 
 	tween := float64(rs.Frame) / float64(rs.Frames)
 
 	colors := teamColors(sNew.Teams)
-	renderBots(sOld, sNew, tween, w, d, colors)
+	renderBots(sOld, sNew, tween, w, colors)
 	renderObstacles(sNew, w)
 
 	rs.Frame++
@@ -33,7 +32,7 @@ func Render(rs RenderState, sOld, sNew game.State, w *pixelgl.Window, d time.Dur
 	return rs
 }
 
-func renderBots(sOld, sNew game.State, tween float64, w *pixelgl.Window, _ time.Duration, colors map[*game.Team]pixel.RGBA) {
+func renderBots(sOld, sNew game.State, tween float64, w *pixelgl.Window, colors map[*game.Team]pixel.RGBA) {
 	bounds := w.Bounds()
 	im := imdraw.New(nil)
 
diff --git a/main.go b/main.go
index e31f5d2..4e54c37 100644
--- a/main.go
+++ b/main.go
@@ -27,8 +27,6 @@ func run() {
 
 	s := game.NewState()
 
-	start := time.Now()
-
 	w.Clear(colornames.Peachpuff)
 
 	rs := gfx.RenderState{
@@ -42,7 +40,7 @@ func run() {
 		case w.Pressed(pixelgl.KeyQ):
 			return
 		case rs.Animating:
-			rs = gfx.Render(rs, sOld, s, w, time.Since(start))
+			rs = gfx.Render(rs, sOld, s, w)
 			if !rs.Animating {
 				sOld = s
 			}