diff --git a/creature.go b/creature.go
index 99e1779..042c726 100644
--- a/creature.go
+++ b/creature.go
@@ -53,7 +53,7 @@ func (machine *Machine) Reset () {
 func (machine *Machine) Execute (offset int) {
 	machine.counter = offset
 
-	for {
+	for machine.counter < len(machine.Program) {
 		switch machine.instruction() {
 		case 0x0:
 			// PUSH
@@ -244,5 +244,11 @@ func (machine *Machine) Unregister (id int) {
 	delete(machine.functions, id)
 }
 
+// LoadMemory loads the contents of block into the machine's memory.
+func (machine *Machine) LoadMemory (block []int) {
+	machine.block = make([]int, len(block))
+	copy(machine.block, block)
+}
+
 // Milk milks the stack machine
 func (machine *Machine) Milk () {}