diff --git a/types.c b/types.c
index 4f03a4e..6c784cc 100644
--- a/types.c
+++ b/types.c
@@ -1,5 +1,6 @@
 
 #include "types.h"
+#include "util/rand.h"
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -41,6 +42,10 @@ Vec2 vec2_Scale(Vec2 v, double scale) {
 }
 
 Vec2 vec2_Random(double minX, double maxX, double minY, double maxY) {
+	Vec2 result = {
+		.x = minX + (maxX - minX) * rand_Double01(),
+		.y = minY + (maxY - minY) * rand_Double01()};
+	return result;
 }
 
 
diff --git a/util/rand.c b/util/rand.c
new file mode 100644
index 0000000..ebd4819
--- /dev/null
+++ b/util/rand.c
@@ -0,0 +1,9 @@
+
+#include "rand.h"
+#include <stdlib.h>
+
+
+double rand_Double01() {
+	// Very bad implementation.
+	return ((double)rand()) / (double)RAND_MAX;
+}
diff --git a/util/rand.h b/util/rand.h
new file mode 100644
index 0000000..c7e3ebd
--- /dev/null
+++ b/util/rand.h
@@ -0,0 +1,12 @@
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// returns a double in the [0,1) range.
+double rand_Double01();
+
+#ifdef __cplusplus
+}
+#endif