didn't finish engineering school: switched to art after two years. then went to art grad school and did a lot of... engineering.
maybe this is why every few years (remember, thirteenth redesign of the grid) i panic after not being confident that the LEDs are on the right way and cannot for the life of me remember which side is anode or cathode and how that relates to the schematic diagram. it's like forgetting basic geometry (which i also do).
so, here, enshrined:
ANODE (+) -|>|- CATHODE (-)
go forth into the light, may you also employ millions of LEDs with great certainty