without any DSP objects[~] and [expr].
JK flip-flop - Wikipedia(en)
The following circuit is a JK-FF circuit consists only of
arithmetic product, logical NOT, and basic PD objects [trigger] and [f].

This circuit simulates continuous feedback loops of logic circuit,
so a proper accuracy is expected.
Its logic context is pretty honest, and leaves the possibility of make more better.
Just do it as you like.
jkff1.pd