diff --git a/sandbox/base/main.c b/sandbox/base/main.c
index 37f7ec6..d89d496 100644
--- a/sandbox/base/main.c
+++ b/sandbox/base/main.c
@@ -10,7 +10,7 @@
 #include <socks/memblock.h>
 #include <socks/vm.h>
 
-#define NR_BTREE_NODES 32
+#define NR_BTREE_NODES 1024
 
 /* we're working with 512MiB of simulated system RAM */
 #define MEMORY_SIZE_MB 512
@@ -169,7 +169,7 @@ void btree_print(btree_node_t *node, int depth)
 			} else {
 				printf("? ");
 			}
-				
+
 		}
 
 		printf("%llu (h:%d)\n", node->b_key, node->b_height);
@@ -230,13 +230,32 @@ static int btree_avl_validate(btree_node_t *x)
 	return height;
 }
 
+static btree_key_t alloc_unique_key(btree_node_t *nodes, size_t count)
+{
+	while (1) {
+		btree_key_t k = (rand() % 8192) + 1;
+
+		for (size_t i = 0; i < count; i++) {
+			if (nodes[i].b_key == k) {
+				continue;
+			}
+		}
+
+		return k;
+	}
+
+	return (btree_key_t)-1;
+}
+
+
+
 static int btree_test(void)
 {
 	btree_t tree = {};
 	btree_node_t *nodes = calloc(NR_BTREE_NODES, sizeof *nodes);
 
 	for (int i = 0; i < NR_BTREE_NODES; i++) {
-		nodes[i].b_key = (rand() % 128) + 1;
+		nodes[i].b_key = alloc_unique_key(nodes, i);
 		printf(" - node %d: %llu\n", i, nodes[i].b_key);
 	}