Ukaz , by auriocus, is a graph widget in pure Tcl/Tk with syntax / functionality based on gnuplot.
ukaz provides a widget to plot data in x-y format for scientific applications. It sets reasonable defaults to display most datasets without the need for individual settings. Ukaž was designed to be easy to use and borrows most of the syntax from the popular gnuplot package, slightly adapted to be more Tcl friendly.