Counter (up and down, switch selected) to
Binary to 7-segment decoder to
7 segment display
Reset push button (to 0 or F)
4 leds show binary status (LSD, right)
Logic train input, adjustable
Colored boxes for continuity to distant objects (RESET to push button)
Adjustable logic train can be be slowed to show 4-led binary counting progression corresponding to 7-segment display
Carry (up) and Borrow (down) Leds
