Place two Observer blocks face-to-face to produce a clock.
Run lines of redstone dust out of both ends and watch it flash.
Connect a redstone lamp to one line and watch it stay on solid as if the signal is constant.
Connect a dropper to the other line and hear it fire as if the signal is oscillating.
Take off the dropper and connect a comparator to the line and watch it act like there is no signal at all.
For a fun lighting effect place a repeater in the middle of the redstone line leading to the redstone lamp (such that there is dust at each end of the repeater). This looks like an interference pattern to me. I could be wrong. Click-up the repeater delay to get different flash rate and solid light again.
Sorry to waste your time if this was intentional design. If so it will make for some interesting circuits moving forward.