@Steven Bos I have added the function that seems to do what you are asking: prev(). I have also added a del() function, that takes a delay parameter, so: •

"Prev_point; outnode prev()"

will create a waveform where outnode (synonym for v(outnode) )delayed exactly by one timestep (whatever the timestep is) •

"Delayed; outnode 20n del()"

will delay the waveform by 20ns. In above example i think the resut is correct, there is a point where both D0 and D1 are at 1.8 and the sum there is 3.6. All other points the sum is stable 1.8. If you want to synchronize the falling edges may be you need to make the pulse width of D1 smaller by 100n or 50n, just do some tests.