New function colour: unsafe

The fact that Array and String are banned by your “utmost safe” feature is a serious flaw, and in my opinion a disqualifying one. Sure, it’s possible to work around them being banned, but what is the advantage of doing so? How does it improve the code? If there is some sort of improvement, does it outweigh the costs of having to invent nonstandard collection types that aren’t used by anything else?

My sense is that nothing of actual value is gained and much is lost by avoiding or limiting use of these common-currency types simply because they are implemented with unsafe operations.