While this is a really nice, entertaining kata to perform we should still be aware that if these tax rates were real they would represent an incredibly regressive taxation policy which would have the poor pay a relatively higher proportion of their income in tax.

Yes it's only an example, but now you've spent a few minutes thinking about how to implement a tax calculator think about what that means for people paying it.

How about as a further technical / sociological exercise use your calculator to work out overall percentage tax on incomes ranging from 5 - 1000.

The Ruby version of this kata does not specify that employees is a global variable $employees.

It seems this is tripping people up, myself included.