An algorithm is a sequence of steps that are usually performed by a computer.

The algorithm doesn't have to be written in any particular programming language or even in a programming language at all; you can write your algorithm in English or any other human language.

Some people call an algorithm written in human language pseudocode. Once you know the steps that the computer will take, you can code your algorithm in the programming language of your choice.

We use the word "input" both for parameters (input names) and for arguments (input values).

A parameter (or formal parameter) is the input name, such as number of branches. The input name is set in the block definition. It never changes.

An argument (or actual argument) is the input value, such as 6 for a hexagonal pinwheel. The input value is given each time the block is run; it can be a different value each time.