First, let's look at a set of primitives. The picture below shows a set of hemispheres available in Yellow's old Object Yard. See how the object's name is the same except for the number. So if you wanted a very small hemisphere, you would select p1hsph0025.rwx. You can basically record the basic object name, like p1hsph1000.rwx and then just note the rest of the number sequence, in this case 1000, 0800, 0500, 0400, 0200, 0100, 0050, 0025.

One commonly used set of these sorts of objects are 2D walls. I have started using them a lot, because of their versatility and ability to take pictures, textures and tints. One set is the w3 panel set, for example, w3pan_1000g.rwx. The interesting thing about the w_panel set is that it has three numbers that will change: X & Y axes, and the texture of the basic wall. The picture illustrates the number changes and what happens.

Note that the number after the w in the object name changes the texture of the object. This number can be used for textures and pictures, in that the more squares appear on the panel, the more tiling you will get on your texture or picture. The w1pan... has the fewest tiles, and the w2pan... has the most. The number after the w3pan_ is the length (X axis) of the panel. The letter after the number gives the Y axis (up and down). The X axis numbers are 1000, 0800, 0500, 0200, and 0100. The letters are c through h. So you can see that these object sets are very versatile and easily used. Try to find more sets in the object yards. There are curves, flats, and a few more lurking about.