diff --git a/modules/intersect.lua b/modules/intersect.lua
index 17ae847..2eee4d5 100644
--- a/modules/intersect.lua
+++ b/modules/intersect.lua
@@ -58,6 +58,40 @@ function intersect.point_aabb(point, aabb)
 		aabb.max.z >= point.z
 end
 
+-- point          is a vec3
+-- frustum.left   is a plane { a, b, c, d }
+-- frustum.right  is a plane { a, b, c, d }
+-- frustum.bottom is a plane { a, b, c, d }
+-- frustum.top    is a plane { a, b, c, d }
+-- frustum.near   is a plane { a, b, c, d }
+-- frustum.far    is a plane { a, b, c, d }
+function intersect.point_frustum(point, frustum)
+	local x, y, z = point:unpack()
+	local planes  = {
+		frustum.left,
+		frustum.right,
+		frustum.bottom,
+		frustum.top,
+		frustum.near,
+		frustum.far or false
+	}
+
+	-- Skip the last test for infinite projections, it'll never fail.
+	if not planes[6] then
+		table.remove(planes)
+	end
+
+	local dot
+	for i = 1, #planes do
+		dot = planes[i].a * x + planes[i].b * y + planes[i].c * z + planes[i].d
+		if dot <= 0 then
+			return false
+		end
+	end
+
+	return true
+end
+
 -- http://www.lighthouse3d.com/tutorials/maths/ray-triangle-intersection/
 -- ray.position  is a vec3
 -- ray.direction is a vec3
@@ -413,10 +447,10 @@ end
 
 -- aabb.min       is a vec3
 -- aabb.max       is a vec3
--- frustum.top    is a plane { a, b, c, d }
--- frustum.bottom is a plane { a, b, c, d }
 -- frustum.left   is a plane { a, b, c, d }
 -- frustum.right  is a plane { a, b, c, d }
+-- frustum.bottom is a plane { a, b, c, d }
+-- frustum.top    is a plane { a, b, c, d }
 -- frustum.near   is a plane { a, b, c, d }
 -- frustum.far    is a plane { a, b, c, d }
 function intersect.aabb_frustum(aabb, frustum)
@@ -428,10 +462,10 @@ function intersect.aabb_frustum(aabb, frustum)
 
 	-- We have 6 planes defining the frustum, 5 if infinite.
 	local planes = {
-		frustum.top,
-		frustum.bottom,
 		frustum.left,
 		frustum.right,
+		frustum.bottom,
+		frustum.top,
 		frustum.near,
 		frustum.far or false
 	}
@@ -493,20 +527,19 @@ end
 
 -- sphere.position is a vec3
 -- sphere.radius   is a number
--- frustum.top     is a plane { a, b, c, d }
--- frustum.bottom  is a plane { a, b, c, d }
 -- frustum.left    is a plane { a, b, c, d }
 -- frustum.right   is a plane { a, b, c, d }
+-- frustum.bottom  is a plane { a, b, c, d }
+-- frustum.top     is a plane { a, b, c, d }
 -- frustum.near    is a plane { a, b, c, d }
 -- frustum.far     is a plane { a, b, c, d }
 function intersect.sphere_frustum(sphere, frustum)
 	local x, y, z = sphere.position:unpack()
-
-	local planes = {
-		frustum.top,
-		frustum.bottom,
+	local planes  = {
 		frustum.left,
 		frustum.right,
+		frustum.bottom,
+		frustum.top,
 		frustum.near
 	}
 
@@ -515,8 +548,8 @@ function intersect.sphere_frustum(sphere, frustum)
 	end
 
 	local dot
-	for p = 1, #planes do
-		dot = planes[p].a * x + planes[p].b * y + planes[p].c * z + planes[p].d
+	for i = 1, #planes do
+		dot = planes[i].a * x + planes[i].b * y + planes[i].c * z + planes[i].d
 
 		if dot <= -sphere.radius then
 			return false
diff --git a/modules/mat4.lua b/modules/mat4.lua
index 0cb75d1..d06b394 100644
--- a/modules/mat4.lua
+++ b/modules/mat4.lua
@@ -520,6 +520,7 @@ function mat4.to_vec4s(a)
 	}
 end
 
+-- http://www.euclideanspace.com/maths/geometry/rotations/conversions/matrixToQuaternion/
 function mat4.to_quat(a)
 	identity(tmp):transpose(a)
 
@@ -541,34 +542,6 @@ function mat4.to_frustum(a, infinite)
 	local t
 	local frustum = {}
 
-	-- Extract the TOP plane
-	frustum.top = {}
-	frustum.top.a = a[4]  - a[2]
-	frustum.top.b = a[8]  - a[6]
-	frustum.top.c = a[12] - a[10]
-	frustum.top.d = a[16] - a[14]
-
-	-- Normalize the result
-	t = sqrt(frustum.top.a * frustum.top.a + frustum.top.b * frustum.top.b + frustum.top.c * frustum.top.c)
-	frustum.top.a = frustum.top.a / t
-	frustum.top.b = frustum.top.b / t
-	frustum.top.c = frustum.top.c / t
-	frustum.top.d = frustum.top.d / t
-
-	-- Extract the BOTTOM plane
-	frustum.bottom = {}
-	frustum.bottom.a = a[4]  + a[2]
-	frustum.bottom.b = a[8]  + a[6]
-	frustum.bottom.c = a[12] + a[10]
-	frustum.bottom.d = a[16] + a[14]
-
-	-- Normalize the result
-	t = sqrt(frustum.bottom.a * frustum.bottom.a + frustum.bottom.b * frustum.bottom.b + frustum.bottom.c * frustum.bottom.c)
-	frustum.bottom.a = frustum.bottom.a / t
-	frustum.bottom.b = frustum.bottom.b / t
-	frustum.bottom.c = frustum.bottom.c / t
-	frustum.bottom.d = frustum.bottom.d / t
-
 	-- Extract the LEFT plane
 	frustum.left.a = a[4]  + a[1]
 	frustum.left.b = a[8]  + a[5]
@@ -596,6 +569,34 @@ function mat4.to_frustum(a, infinite)
 	frustum.right.c = frustum.right.c / t
 	frustum.right.d = frustum.right.d / t
 
+	-- Extract the BOTTOM plane
+	frustum.bottom = {}
+	frustum.bottom.a = a[4]  + a[2]
+	frustum.bottom.b = a[8]  + a[6]
+	frustum.bottom.c = a[12] + a[10]
+	frustum.bottom.d = a[16] + a[14]
+
+	-- Normalize the result
+	t = sqrt(frustum.bottom.a * frustum.bottom.a + frustum.bottom.b * frustum.bottom.b + frustum.bottom.c * frustum.bottom.c)
+	frustum.bottom.a = frustum.bottom.a / t
+	frustum.bottom.b = frustum.bottom.b / t
+	frustum.bottom.c = frustum.bottom.c / t
+	frustum.bottom.d = frustum.bottom.d / t
+
+	-- Extract the TOP plane
+	frustum.top = {}
+	frustum.top.a = a[4]  - a[2]
+	frustum.top.b = a[8]  - a[6]
+	frustum.top.c = a[12] - a[10]
+	frustum.top.d = a[16] - a[14]
+
+	-- Normalize the result
+	t = sqrt(frustum.top.a * frustum.top.a + frustum.top.b * frustum.top.b + frustum.top.c * frustum.top.c)
+	frustum.top.a = frustum.top.a / t
+	frustum.top.b = frustum.top.b / t
+	frustum.top.c = frustum.top.c / t
+	frustum.top.d = frustum.top.d / t
+
 	-- Extract the NEAR plane
 	frustum.near = {}
 	frustum.near.a = a[4]  + a[3]
diff --git a/spec/mat4_spec.lua b/spec/mat4_spec.lua
index 19dd073..88067dc 100644
--- a/spec/mat4_spec.lua
+++ b/spec/mat4_spec.lua
@@ -100,8 +100,18 @@ describe("mat4:", function()
 
 	it("tests multiplication", function()
 		do
-			local a = mat4 { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 }
-			local b = mat4 { 1, 5, 9, 13, 2, 6, 10, 14, 3, 7, 11, 15, 4, 8, 12, 16 }
+			local a = mat4 {
+				1,  2,  3,  4,
+				5,  6,  7,  8,
+				9,  10, 11, 12,
+				13, 14, 15, 16
+			}
+			local b = mat4 {
+				1, 5, 9,  13,
+				2, 6, 10, 14,
+				3, 7, 11, 15,
+				4, 8, 12, 16
+			}
 			local c = mat4():mul(a, b)
 			assert.is.equal(c[1],  30)
 			assert.is.equal(c[2],  70)
@@ -125,13 +135,18 @@ describe("mat4:", function()
 		end
 
 		do
-			local a = mat4 { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 , 13, 14, 15, 16 }
+			local a = mat4 {
+				1,  2,  3,  4,
+				5,  6,  7,  8,
+				9,  10, 11, 12,
+				13, 14, 15, 16
+			}
 			local b = { 10, 20, 30, 40 }
 			local c = mat4.mul_mat4x1({}, a, b)
-			assert.is.equal(c[1],  900)
-			assert.is.equal(c[2],  1000)
-			assert.is.equal(c[3],  1100)
-			assert.is.equal(c[4],  1200)
+			assert.is.equal(c[1], 900)
+			assert.is.equal(c[2], 1000)
+			assert.is.equal(c[3], 1100)
+			assert.is.equal(c[4], 1200)
 		end
 	end)
 
@@ -172,7 +187,12 @@ describe("mat4:", function()
 	end)
 
 	it("tests transpose", function()
-		local a = mat4 { 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3 ,3 ,4, 4 ,4 ,4 }
+		local a = mat4 {
+			1, 1, 1, 1,
+			2, 2, 2, 2,
+			3, 3, 3, 3,
+			4, 4, 4, 4
+		}
 		local b = mat4():transpose(a)
 		assert.is.equal(b[1],  1)
 		assert.is.equal(b[2],  2)
@@ -211,8 +231,6 @@ describe("mat4:", function()
 
 	it("tests convertions", function()
 		local a = mat4()
-		local b = mat4 { 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4 }
-
 		local v = a:to_vec4s()
 		assert.is_true(type(v)    == "table")
 		assert.is_true(type(v[1]) == "table")
@@ -236,11 +254,17 @@ describe("mat4:", function()
 		assert.is.equal(v[4][3], 0)
 		assert.is.equal(v[4][4], 1)
 
+		local b = mat4 {
+			0, 0, 1, 0,
+			1, 0, 0, 0,
+			0, 1, 0, 0,
+			0, 0, 0, 0
+		}
 		local q = b:to_quat()
-		--assert.is.equal(q.x, 0)
-		--assert.is.equal(q.y, 0)
-		--assert.is.equal(q.z, 0)
-		--assert.is.equal(q.w, 0)
+		assert.is.equal(q.x, -0.5)
+		assert.is.equal(q.y, -0.5)
+		assert.is.equal(q.z, -0.5)
+		assert.is.equal(q.w,  0.5)
 	end)
 end)