Yes. Left a 1/4" line of clear on a 38mm by 3.5"long blank. Closed at one end. The clear line turns into a clear spot on the closed end.

Pop a hole on the end, start snipping the clear line after you do your pattern on the outside.

I usually punty up 12mm rod, and keep cutting and paddle into a big flat book mark looking plate.

Then keep heating either half, one at a time, and curl it ISO. The clear gives you something to grab, and something to smush back onto the color bits (clear distorts)

Best tip, use your bowl push to shape each half of the book mark back into a "curl" like a wave shape. The two waves come together into a tube again.

It happens surprisingly fast. (compared to in my minds eye)