Here's the start of an idea for a plot that might serve as a logo for J. The cross-section is a "heart" but it needs work to have more of a "J" shape for the tube as a whole.
I created this with the following sequence:
load 'plot' load 'bmppal.ijs' RGCLR_jwplot_=: ADJPAL 'type surface;mesh 0' plot -j./~(1 o. 2*t) j. 1 o. 3*t=. 1p1*100%~i.101
where "bmppal.ijs" is the code found here.