BLT is an extension to Tcl/Tk. It adds plotting widgets (X-Y graph, barchart, stripchart), a powerful geometry manager, a new canvas item, and several new commands to Tk. Plotting widgets: graph, barchart, stripchart Hierarchical list box: hierbox Tab set: tabset Geometry Manager: table Vector Data Object: vector Background Program Execution: bgexec Busy Command: busy New Canvas Item: eps Drag & Drop Facility: drag&drop Bitmap Command: bitmap Miscellaneous Commands: winop, bltdebug, watch, spline, htext