This project shows how to use an input slot or "parameter" in a block you create. This project has a custom block named "burst" that draws a starburst -- just a bunch of lines coming out of a single point. In the block definition hat for "burst" is something that looks like a variable reporter called "number of lines". You can drag out copies of that block and stick it into the input slots of command blocks in the script for "burst". In this case, "number of lines" was used in the "repeat" block and also in the turn block. ("360 / number of lines" gives the angle to turn after drawing each line to make the lines spread evenly around a circle.) Every time the green flag is clicked, the "burst" block is run with a random number. That number becomes the value of "number of lines" inside the "burst" script. Of course, you can take the "random" block out of the brown "burst" command and and type in your own number, but then it would be the same every time. How do you make a block that has a parameter? It's a several step process. First, make a simple named block. That will create a block definition hat in the scripting area. Shift-click on that hat and select "edit procedure name and parameters" from the menu. That will bring up a dialog box. You can click on the block name to change change the name. Click on one of the three parameter shapes to add a parameter of the given shape. For example, you could click on the oval shape to add a number parameter. You will probably want to edit the name of the parameter from "n1" to something that makes sense for your block (such as "number of lines"). To delete a parameter, click to the right of it and hit the backspace or delete key. When you're finished editing, click "ok". After you've added a parameter, the block in the "More Blocks" will have an input slot and the block definition hat will have a parameter reporter.
