diff --git a/modules/mat4.lua b/modules/mat4.lua
index 7db4c5a..9c136ee 100644
--- a/modules/mat4.lua
+++ b/modules/mat4.lua
@@ -665,7 +665,7 @@ function mat4.to_string(a)
 	return str
 end
 
---- Convert a matrix to vec4s.
+--- Convert a matrix to row vec4s.
 -- @tparam mat4 a Matrix to be converted
 -- @treturn table vec4s
 function mat4.to_vec4s(a)
@@ -677,6 +677,18 @@ function mat4.to_vec4s(a)
 	}
 end
 
+--- Convert a matrix to col vec4s.
+-- @tparam mat4 a Matrix to be converted
+-- @treturn table vec4s
+function mat4.to_vec4s_cols(a)
+	return {
+		{ a[1], a[5], a[9],  a[13] },
+		{ a[2], a[6], a[10], a[14] },
+		{ a[3], a[7], a[11], a[15] },
+		{ a[4], a[8], a[12], a[16] }
+	}
+end
+
 -- http://www.euclideanspace.com/maths/geometry/rotations/conversions/matrixToQuaternion/
 --- Convert a matrix to a quaternion.
 -- @tparam mat4 a Matrix to be converted
diff --git a/spec/mat4_spec.lua b/spec/mat4_spec.lua
index 19b0fff..7e76122 100644
--- a/spec/mat4_spec.lua
+++ b/spec/mat4_spec.lua
@@ -322,7 +322,12 @@ describe("mat4:", function()
 	end)
 
 	it("converts a matrix to vec4s", function()
-		local a = mat4()
+		local a = mat4 {
+			1,  2,  3,  4,
+			5,  6,  7,  8,
+			9,  10, 11, 12,
+			13, 14, 15, 16
+		}
 		local v = a:to_vec4s()
 		assert.is_true(type(v)    == "table")
 		assert.is_true(type(v[1]) == "table")
@@ -330,25 +335,60 @@ describe("mat4:", function()
 		assert.is_true(type(v[3]) == "table")
 		assert.is_true(type(v[4]) == "table")
 
-		assert.is.equal(1, v[1][1])
-		assert.is.equal(0, v[1][2])
-		assert.is.equal(0, v[1][3])
-		assert.is.equal(0, v[1][4])
+		assert.is.equal(1,  v[1][1])
+		assert.is.equal(2,  v[1][2])
+		assert.is.equal(3,  v[1][3])
+		assert.is.equal(4,  v[1][4])
 
-		assert.is.equal(0, v[2][1])
-		assert.is.equal(1, v[2][2])
-		assert.is.equal(0, v[2][3])
-		assert.is.equal(0, v[2][4])
+		assert.is.equal(5,  v[2][1])
+		assert.is.equal(6,  v[2][2])
+		assert.is.equal(7,  v[2][3])
+		assert.is.equal(8,  v[2][4])
 
-		assert.is.equal(0, v[3][1])
-		assert.is.equal(0, v[3][2])
-		assert.is.equal(1, v[3][3])
-		assert.is.equal(0, v[3][4])
+		assert.is.equal(9,  v[3][1])
+		assert.is.equal(10, v[3][2])
+		assert.is.equal(11, v[3][3])
+		assert.is.equal(12, v[3][4])
 
-		assert.is.equal(0, v[4][1])
-		assert.is.equal(0, v[4][2])
-		assert.is.equal(0, v[4][3])
-		assert.is.equal(1, v[4][4])
+		assert.is.equal(13, v[4][1])
+		assert.is.equal(14, v[4][2])
+		assert.is.equal(15, v[4][3])
+		assert.is.equal(16, v[4][4])
+	end)
+
+	it("converts a matrix to vec4s, column-wise", function()
+		local a = mat4 {
+			1,  2,  3,  4,
+			5,  6,  7,  8,
+			9,  10, 11, 12,
+			13, 14, 15, 16
+		}
+		local v = a:to_vec4s_cols()
+		assert.is_true(type(v)    == "table")
+		assert.is_true(type(v[1]) == "table")
+		assert.is_true(type(v[2]) == "table")
+		assert.is_true(type(v[3]) == "table")
+		assert.is_true(type(v[4]) == "table")
+
+		assert.is.equal(1,  v[1][1])
+		assert.is.equal(5,  v[1][2])
+		assert.is.equal(9,  v[1][3])
+		assert.is.equal(13, v[1][4])
+
+		assert.is.equal(2,  v[2][1])
+		assert.is.equal(6,  v[2][2])
+		assert.is.equal(10, v[2][3])
+		assert.is.equal(14, v[2][4])
+
+		assert.is.equal(3,  v[3][1])
+		assert.is.equal(7,  v[3][2])
+		assert.is.equal(11, v[3][3])
+		assert.is.equal(15, v[3][4])
+
+		assert.is.equal(4,  v[4][1])
+		assert.is.equal(8,  v[4][2])
+		assert.is.equal(12, v[4][3])
+		assert.is.equal(16, v[4][4])
 	end)
 
 	it("converts a matrix to a quaternion", function()