just come across what seems like a mistake in the reference for jit.lcd. the pensize command takes 2 integer arguments as opposed to 1. in the help file it actually has 2 arguments.
quote from reference file:
pensize number-of-pixels [int] Sets the pen size to be used subsequent drawing operations. The pen size is set with a single integer argument.
not a biggy but pensize message will not work unless it receives 2 integers...