This is a toy example of a verified compiler. It starts from a "high-level" language of natural numbers, Booleans, conditional statements, and conjunction. The compilation target is a stack machine over natural numbers with instructions for pushing constants, performing conjunction, as well as conditional and unconditional jumps forward. The compiler performs a restricted form of constant folding on the high-level language before lowering terms to stack machine programs. We show that the compiler is semantics preserving by proving that evaluation of high-level terms produces an equivalent result to executing the corresponding stack machine.