Open strap Rack and snail strike Off-center pendulum
Open strap; Count wheel strike; Off-center pendulum
Terry-style post foot Cutout in upper strap too far left Count wheel retainer spring like question mark
Thomas-style post foot Cutout in upper strap is centered Count wheel retainer spring like question mark
Thomas-style post foot Cutout in upper strap is centered Count wheel retainer spring like reversed question mark
Solid plates Outside escapement Count wheel strike Movement attached to face Centered pendulum
Solid plates Inside-outside escapement Movement attached to back plate Escapement attached to front plate Centered pendulum