diff --git a/scratchpad/core.c b/scratchpad/core.c
deleted file mode 100644
index 20b59e5..0000000
--- a/scratchpad/core.c
+++ /dev/null
@@ -1,27 +0,0 @@
-
-uint64_t xorshift64(uint64_t* seed)
-{
-    // Algorithm "xor" from p. 4 of Marsaglia, "Xorshift RNGs"
-    // <https://en.wikipedia.org/wiki/Xorshift>
-    uint64_t x = *seed;
-    x ^= x << 13;
-    x ^= x >> 7;
-    x ^= x << 17;
-    return *seed = x;
-}
-
-double sample_unit_uniform(uint64_t* seed)
-{
-    // samples uniform from [0,1] interval.
-    return ((double)xorshift64(seed)) / ((double)UINT64_MAX);
-}
-
-double sample_unit_normal(uint64_t* seed)
-{
-    // // See: <https://en.wikipedia.org/wiki/Box%E2%80%93Muller_transform>
-    double u1 = sample_unit_uniform(seed);
-    double u2 = sample_unit_uniform(seed);
-    double z = sqrtf(-2.0 * log(u1)) * sin(2 * PI * u2);
-    return z;
-}
-
diff --git a/scratchpad/quickselect/makefile b/scratchpad/quickselect/makefile
new file mode 100644
index 0000000..c755523
--- /dev/null
+++ b/scratchpad/quickselect/makefile
@@ -0,0 +1,5 @@
+build:
+	gcc quickselect.c -lm -o quickselect
+
+run:
+	./quickselect
diff --git a/scratchpad/quickselect/quickselect b/scratchpad/quickselect/quickselect
new file mode 100755
index 0000000..e3c99f2
Binary files /dev/null and b/scratchpad/quickselect/quickselect differ
diff --git a/scratchpad/quickselect/quickselect.c b/scratchpad/quickselect/quickselect.c
new file mode 100644
index 0000000..c3607f9
--- /dev/null
+++ b/scratchpad/quickselect/quickselect.c
@@ -0,0 +1,8 @@
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(){
+  printf("Hello world!\n");
+  return 0;
+}