1. FILE MENU. It contains "open", "save", "save PS" and "quit" items. "save PS" will save the picture as a post script file. 2. SIZE MENU. One can choose the radius of the knot tube here. The default value is 2. 3. COLOR MENU. There are three ways to color the knot. (i) "periodic": The color is changed periodically when traveling along the knot. Default period is 1, and can be changed by "set color period". (ii) "depth": The color is determined by the z-coordinate of the point. (iii) "single": Use single color. With "choose knot color" one can choose several preset single colors for the knot. The next two items will bring up color editors for the knot (with single color) and the background. Click on the toggle buttons of the color editor to bring up the color map. The beckground color is specified by the diffuse color on the color editor. The last item prints the command "color_period" for setting color period. See "On commands" for more details. 4. RENDER MENU. Rendering by line is the fastest. Rendering by tube is the default, and is probably the best. When the vertex number is small, rendering by cylinder-ball will show round vertices, but it is slow when vertex number is large. The 4th menu item prints the command for setting the tube sides. Try commands "t 1", "t 2" "t 3" and "t 10" to see the difference. 5. OPTIONS MENU. (i) The first item toggles antialiasing on/off. When it is turned on, it set antialiasing level to 10. See "On commands" for more details. (ii) The second item toggles rough run on/off. When rough run is on, each vertex of the knot is moved according to its own gradient. This method approaches the minimal energy faster for many knots, but it is not accurate. (iii) "add pinch force". This item is important when one wants to find the minimum number of edges to represent a knot. If this is off, the "delete" command will only try to delete vertices without changing the other vertices. If "add pinch force" is on, it add some extra force on certain edges, trying to pinch it to a point so that certain vertex can be removed. The other two items prints commands for setting antialiasing level and pinch edge. See "On commands". 6. HELP MENU. Print these help messages.