The polychrome strobe can flash multiple colors of light. Each color flashes at the same
frequency, but there can be a phase shift between the colors. Polychrome strobe helps you
to see certain features the occur with repetitive motion that may be harder to see using
ordinary strobe light.
This video explains how the polychrome strobe makes water waves appear to move in slow motion
and in color
This video shows how polychrome strobe light can highlight important features of water wave interference.
You can build your own polychrome strobe
for a resonable price (less than 25 dollars).