Just some things to think about if anyone wishes to duplicate Light Logic.

1 - There is a wide low end resistance value range with CdS photo cells so try to test and match the cells used.

2 - Stray light will kill the Light Logic effect faster than anything else.  Light shielding around the Led/Ldr pair IS required.

3 - Operating voltage is very critical and selection of support resistors is somewhat trial and error.

Light Logic in its current development is still very experimental and requires a lot of hands on adjustments.