diff --git a/src/Instructions/CodeInstructions.hs b/src/Instructions/CodeInstructions.hs
index 6a5721a..b29381c 100644
--- a/src/Instructions/CodeInstructions.hs
+++ b/src/Instructions/CodeInstructions.hs
@@ -20,6 +20,7 @@ extractFirstFromBlock (Block (x : _)) = x
 extractFirstFromBlock gene = gene
 
 extractLastFromBlock :: Gene -> Gene
+extractLastFromBlock (Block []) = Block []
 extractLastFromBlock (Block xs) = last xs
 extractLastFromBlock gene = gene