@rloic already provided a link to the sketch, but I’ll answer your other question.
No, LockLayer() and MoveToLayer() are not equivalent. LockLayer(N) toggles the state of layer N when pressed, activating or deactivating that layer, but leaving all other layers unaffected. MoveToLayer(N) unconditionally activates layer N, and also deactivates all other layers (except the base layer).
The distinction matters because the layer stack is index-ordered. Layer N+1 is always above (and when active, its non-transparent keys will be masking) Layer N, regardless of the order in which they were activated. So, if both layers 2 and 3 are active, pressing LockLayer(2) will deactivate layer 2, but would only affect the mapping of keys that are transparent on layer 3. Pressing LockLayer(2) again would re-activate layer 2, but layer 3 will still be the top layer. Pressing MoveToLayer(2), however, will also deactivate layer 3, and will result in layer 2 being active regardless of its previous status.