How to get the traces on Igor' logo

I mean the traces on the About Igor Pro panel and the trace on the small icon of a .pxp file.

The traces look like a Bessel funtion or a Sinc functuon (and a one I can not figure out) but I am not sure.

Yes, Bessel functions. This is pretty close:
make/n=1000 junk
setscale/I x -25,25,junk
duplicate junk, junk2
junk2 = bessj(1,x)
Display junk, junk2

John Weeks
WaveMetrics, Inc.