I was building the Snap Circuit of Mega Pulser & Flasher, but not working, anyone have any idea how to get this one working?

I got the Snap Circuit Extreme that have 750 Snap Circuit Projects to build from.
I built many different (samples of) projects from the 5 project booklets-most of them are working while several other ones not working, then on Project #604 - I tried building the Snap Circuit Project of 'Mega Pulser & Flasher', then that didn't work, & I tried building that one again, still don't work.