Radicals ( Radical8) two strokes in Kanji;

dimensional, e.g.

IFF electronic, it can be one of the Schematic Symbols i.e. to do (connect, disconnect) between nodes;

www.jisho.org radical number 8 ... ;

directional, e.g.

;

logical, e.g.

in Hiragana: lid;
something to be capped (controlled from above) e.g. x variable to be controlled by y variable;
something to be limited e.g. y variable's value;

numerological, e.g.

2;

structural, e.g.

supercomputer (e.g. The K computer), also see: Computers;

x variable to be controlled by y variable;

Radicals;