diff --git a/main.c b/main.c
index 9510dc7..f88eb07 100644
--- a/main.c
+++ b/main.c
@@ -4,6 +4,7 @@
 
 #define ALIGN4(s) (((((s)-1)>>2)<<2)+4)
 #define BLOCK_SIZE sizeof(struct block)
+#define MINIMUM_BLOCK_SIZE  16
 
 /// The memory block's header.
 struct block
@@ -22,6 +23,10 @@ struct block* last = NULL;
 /// @returns The new memory block.
 struct block* extend_heap(size_t s)
 {
+	// Ensure the allocated size is at least the minimum block size
+	if (s < MINIMUM_BLOCK_SIZE)
+		s = MINIMUM_BLOCK_SIZE;
+
 	struct block* b = sbrk(0);
 
 	if (sbrk(BLOCK_SIZE + s) == (void*)-1)