Found it. in ajgraph.c starting at line 2760: xa[0] = x; ya[0] = y + incr; xa[1] = x + incr; ya[1] = y + size; xa[2] = x + size; ya[2] = y + incr; xa[3] = x + incr; ya[3] = y; xa[4] = x; ya[4] = y; the last line should be ya[4] = y + incr; Regards, David Mathog mathog at caltech.edu Manager, Sequence Analysis Facility, Biology Division, Caltech