Timed: connect the terminals through the nodes to send the correct signal as quickly as possible
Untimed: connect the terminals through the nodes to send the correct signal while crossing as many colored nodes as possible — there's no timer, and the board is densely packed with colored nodes to route through
Rules
Each edge can only be used once
Crossing a colored node toggles its color; a black node turns all colors off, a white node turns them all on (Untimed boards never use black or white nodes)
A dotted edge needs its color on to cross; a crossing line needs its color off to cross
In Untimed, a node can be crossed again later (via a different edge) to flip its color back — it still counts toward your score the first time