A few months ago I tattooed a fork bomb on my arm, and I skipped the whitespaces, because I think it looks nicer without them. But to my dismay, sometimes (not always) when I run it in a shell it doesn't start a fork bomb, but it just gives a syntax error.

bash: syntax error near unexpected token `{:'

Yesterday it happened when I tried to run it in a friend's Bash shell, and then I added the whitespace and it suddenly worked, :(){ :|:& };: instead of :(){:|:&};:

Does the whitespace matter; have I tattooed a syntax error on my arm?!

It seems to always work in zsh, but not in Bash.

A related question does not explain anything about the whitespaces, which really is my question; Why is the whitespace needed for Bash to be able to parse it correctly?