Rubber Sheet
It IS about physics. It ALL is.
It IS about physics. It ALL is.
This comic refers to a common analogy used to explain how mass distorts space-time — a bowling ball resting on a sheet of rubber distorts the sheet due to its weight. The system has some qualitative features in common with gravity; it's often misused to show that "mass warps spacetime" (895: Teaching Physics).
The next part of the original analogy explains a black hole: the slope of the sheet becomes so deep that you can't climb out from the bottom any more, similar to a black hole, which even light can't escape from. However, the comic subverts the analogy, and the sheet becomes a trampoline instead.
Reading onwards, it seems that Beret Guy is just messing about with the scenario.
The line "Imagining is fun!" is also a homage to Richard P. Feynman's "Fun to Imagine" Series of Interviews. The power of Beret Guy's imagination—so that he can physically experience what he imagines—is reminiscent of 248: Hypotheticals.
The title text also states that the rubber sheet, broken rope and trampoline are still all about physics (see also 435: Purity).