diff --git a/engine/physics/src/minimum_difference.rs b/engine/physics/src/minimum_difference.rs
index f234bc71..567454db 100644
--- a/engine/physics/src/minimum_difference.rs
+++ b/engine/physics/src/minimum_difference.rs
@@ -9,6 +9,266 @@ use MinkowskiVert::VertVert as PQ;
 const SIMPLEX_TETRAHEDRON:usize=4;
 type Simplex=arrayvec::ArrayVec<MinkowskiVert,SIMPLEX_TETRAHEDRON>;
 
+/*
+local function absDet(r, u, v, w)
+	if w then
+		return math.abs((u - r):Cross(v - r):Dot(w - r))
+	elseif v then
+		return (u - r):Cross(v - r).magnitude
+	elseif u then
+		return (u - r).magnitude
+	else
+		return 1
+	end
+end
+*/
+
+/*
+local function choosePerpendicularDirection(d)
+	local x, y, z = d.x, d.y, d.z
+	local best = math.min(x*x, y*y, z*z)
+	if x*x == best then
+		return Vector3.new(y*y + z*z, -x*y, -x*z)
+	elseif y*y == best then
+		return Vector3.new(-x*y, x*x + z*z, -y*z)
+	else
+		return Vector3.new(-x*z, -y*z, x*x + y*y)
+	end
+end
+*/
+
+/*
+local function chooseAnyDirection()
+	return Vector3.new(1, 0, 0)
+end
+*/
+
+/*
+local function reduceSimplex0(a0, a1)
+	--debug.profilebegin("reduceSimplex0")
+	local a = a1 - a0
+
+	local p = -a
+
+	local direction = p
+	if direction.magnitude == 0 then
+		direction = chooseAnyDirection()
+	end
+	return direction, a0, a1
+end
+*/
+
+/*
+local function reduceSimplex1(a0, a1, b0, b1)
+	--debug.profilebegin("reduceSimplex1")
+	local a = a1 - a0
+	local b = b1 - b0
+
+	local p = -a
+	local u = b - a
+
+	-- modify to take into account the radiuses
+	local p_u = p:Dot(u)
+
+	if p_u >= 0 then
+		local direction = u:Cross(p):Cross(u)
+		if direction.magnitude == 0 then
+			direction = choosePerpendicularDirection(u)
+		end
+		-- modify the direction to take into account a0R and b0R
+		return direction, a0, a1, b0, b1
+	end
+
+	local direction = p
+	if direction.magnitude == 0 then
+		direction = choosePerpendicularDirection(u)
+	end
+	return direction, a0, a1
+end
+*/
+
+/*
+local function reduceSimplex2(a0, a1, b0, b1, c0, c1)
+	--debug.profilebegin("reduceSimplex2")
+	local a = a1 - a0
+	local b = b1 - b0
+	local c = c1 - c0
+
+	local p = -a
+	local u = b - a
+	local v = c - a
+
+	local uv = u:Cross(v)
+	local up = u:Cross(p)
+	local pv = p:Cross(v)
+	local uv_up = uv:Dot(up)
+	local uv_pv = uv:Dot(pv)
+
+	--print("simples 2 i j", uv_up, uv_pv)
+
+	if uv_up >= 0 and uv_pv >= 0 then
+		--print("and we got here??")
+		local uvp = uv:Dot(p)
+		local direction = uvp < 0 and -uv or uv
+		return direction, a0, a1, b0, b1, c0, c1
+	end
+
+	--print("no we got here")
+
+	local u_u = u:Dot(u)
+	local v_v = v:Dot(v)
+	local uDist = uv_up/(u_u*v.magnitude)
+	local vDist = uv_pv/(v_v*u.magnitude)
+	local minDist2 = math.min(uDist, vDist)
+
+	if vDist == minDist2 then
+		u = v
+		b0 = c0
+		b1 = c1
+		up = -pv
+		uv = -uv
+		u_u = v_v
+	end
+
+	local p_u = p:Dot(u)
+
+	if p_u >= 0 then
+		local direction = up:Cross(u)
+		--print("got here!")
+		if direction.magnitude == 0 then
+			--print("the magnitude is 0")
+			direction = uv
+		end
+		return direction, a0, a1, b0, b1
+	end
+
+	local direction = p
+	if direction.magnitude == 0 then
+		direction = uv
+	end
+	return direction, a0, a0
+end
+*/
+
+/*
+-- a is always the new one
+local function reduceSimplex3(a0, a1, b0, b1, c0, c1, d0, d1)
+	--debug.profilebegin("reduceSimplex3")
+	local a = a1 - a0
+	local b = b1 - b0
+	local c = c1 - c0
+	local d = d1 - d0
+
+	local p = -a
+	local u = b - a
+	local v = c - a
+	local w = d - a
+
+	local uv = u:Cross(v)
+	local vw = v:Cross(w)
+	local wu = w:Cross(u)
+	local uvw = uv:Dot(w)
+	local pvw = vw:Dot(p)
+	local upw = wu:Dot(p)
+	local uvp = uv:Dot(p)
+
+	if pvw/uvw >= 0 and upw/uvw >= 0 and uvp/uvw >= 0 then
+		local direction = Vector3.new(0, 0, 0)
+		return direction, a0, a1, b0, b1, c0, c1, d0, d1
+	end
+
+	local uvwSign = uvw < 0 and -1 or uvw > 0 and 1 or 0
+	local uvDist = uvp*uvwSign/uv.magnitude
+	local vwDist = pvw*uvwSign/vw.magnitude
+	local wuDist = upw*uvwSign/wu.magnitude
+	local minDist3 = math.min(uvDist, vwDist, wuDist)
+
+	if vwDist == minDist3 then
+		u, v = v, w
+		b0, c0 = c0, d0
+		b1, c1 = c1, d1
+		uv = vw
+		uvp = pvw
+	elseif wuDist == minDist3 then
+		u, v = w, u
+		b0, c0 = d0, b0
+		b1, c1 = d1, b1
+		uv = wu
+		uvp = upw
+	end
+
+	local up = u:Cross(p)
+	local pv = p:Cross(v)
+	local uv_up = uv:Dot(up)
+	local uv_pv = uv:Dot(pv)
+
+	if uv_up >= 0 and uv_pv >= 0 then
+		local direction = uvw < 0 and uv or -uv
+		return direction, a0, a1, b0, b1, c0, c1
+	end
+
+	local u_u = u:Dot(u)
+	local v_v = v:Dot(v)
+	local uDist = uv_up/(u_u*v.magnitude)
+	local vDist = uv_pv/(v_v*u.magnitude)
+	local minDist2 = math.min(uDist, vDist)
+
+	if vDist == minDist2 then
+		u = v
+		b0 = c0
+		b1 = c1
+		up = -pv
+		uv = -uv
+		u_u = v_v
+	end
+
+	local p_u = p:Dot(u)
+
+	if p_u >= 0 then
+		local direction = up:Cross(u)
+		if direction.magnitude == 0 then
+			direction = uvw < 0 and uv or -uv
+		end
+		return direction, a0, a1, b0, b1
+	end
+
+	local direction = p
+	if direction.magnitude == 0 then
+		direction = uvw < 0 and uv or -uv
+	end
+	return direction, a0, a1
+end
+*/
+
+/*
+local function reduceSimplex(a0, a1, b0, b1, c0, c1, d0, d1)
+	if d0 then
+		return reduceSimplex3(a0, a1, b0, b1, c0, c1, d0, d1)
+	elseif c0 then
+		return reduceSimplex2(a0, a1, b0, b1, c0, c1)
+	elseif b0 then
+		return reduceSimplex1(a0, a1, b0, b1)
+	elseif a0 then
+		return reduceSimplex0(a0, a1)
+	else
+		error("can a simplex have 0 points?")
+	end
+end
+*/
+
+fn reduce_simplex(
+	simplex:Simplex,
+)->(Planar64Vec3,Simplex){
+	match simplex.as_slice(){
+		&[p0,p1,p2,p3]=>reduce_simplex_4(p0,p1,p2,p3),
+		&[p0,p1,p2]=>reduce_simplex_3(p0,p1,p2),
+		&[p0,p1]=>reduce_simplex_2(p0,p1),
+		&[p0]=>reduce_simplex_1(p0),
+		&[]=>reduce_simplex_0(),
+		_=>unreachable!(),
+	}
+}
+
 enum Expanded{
 	Expanded,
 	Unexpanded,