Scratch code writing

1、Join

1. Hold down the left mouse button to select the code block
2. Drag the code block to the editing area

2、Combination

1. Drag the code block you want to combine to the position you want to combine
2. After the gray connection diagram appears, put down the code block.

3、Delete

method one：

1. Hold down the left mouse button and select the code block you want to delete.
2. Drag the code block to the script (code) area

Method Two：

1. Right click on the code you want to delete
2. Left click on "Delete Code Block"

4、Multiple sets of code relationships

Multi-threaded relationship: the relationship of executing multiple programs at the same time