In Berkeley Snap!, I've developed a "block" that applies Heron's Formula (calculating the area of a triangle given the length of the three sides). It functions, but an error is reported. Below is a screen image that encapsulates everything. (FYI, the graphic below shows three such blocks with the names HF2, HF, and Herons Formula. In an effort to solve the issue, I made all three.)
125.14 is calculated correctly by the method, but it also flags a "internal error" that the "reporter didn't mention." Nonetheless, the block does report, as you can see in my block editor box.
That's just a limitation new users have. You should be able to post images and links if you are on the forum for a bit. Basically just once your name isn't grey.
Make sure you used a [scratchblocks] report [] :: control cap [/scratchblocks] block at the end.
P.S. use [scratchblocks] (insert code here) [scratchcbloks] to make images of blocks without inserting media.
The downside with doing that, is that you can't drag and drop the scratchblocks into snap to get the blocks. That's one reason to use script pics instead.