only did a short test with this one, but it seems to work.
flatbet 18 numbers - always bet for the same side of the wheel to hit
red-low---black-high (same side)
black-low---red-high (same side)
trigger: wait for a switch of sides, then bet for the same half side of the wheel.
for an example red low hits then red high (a switch of sides) then you bet all black-low---red-high (same side)
or
red low hits then black low (switch of sides) then you bet all black-low---red-high (same side)
after one hit, you wait for a new trigger (a new switch of sides)