It’s been awhile since the last one, so cheers for round four! Given that: It’s White selfmate themselves in exactly 5 moves, i.e after. White’s fifth move, Black’s only legal move/s is/are to checkmate White. White has pawn on the second rank Construct a position such that: White’s second...

The following tri-bladed boomerang shape: ... can be folded onto the surface of an octahedron in a way that perfectly covers the entire octahedron with no gaps and no overlaps. How can it be done?

A Tyobrien riddle of the week: With three, I’m an animal With four, I’m a cloth With five, I’m a scene With all six, I’m set free

When making multiple guesses to a question would it be better to update an existing answer or posting a new answer? Surely in the case where the new answer is worked on top of the existing one or with slight modifications, it’s best to update an existing post. How about times where the answers a...

0,0,16,28,77,144,264 What is the next number in the sequence? Note: This sequence is not found on OEIS

Consider the following encoding in 8B6T scheme: $$00000000 \quad \to \quad -+00-+$$ $$00000001\quad \to \quad 0-+-+0$$ $$00000010\quad \to \quad 0-+0-+$$ $$.$$ $$.$$ $$.$$ $$11111111 \quad \to \quad 00+-0+$$ as given here where the $8$ bits are encoded as a pattern of $6$ signal elements ,where t...

Four mathematicians, none yet a centenarian, meet for coffee. The graph-theorist among them noticed that the common divisor graph of their ages (that is, the graph whose vertices are their ages, two of which are joined by an edge if, and only if, they have a common divisor greater than 1) is the ...

I'm a shocker in soccer; An attack with store racks; I sell while you yell, And let rage be gone when switched on. What am I? But there's a twist - I sort of lied to you, if you can figure out how.

Solve the clues, fit them into the crossword grid, and discover (via the shaded and circled cells) a 9-letter pun. Use this and the answers you have found to explain what's going on here! Clues: Halfway round from N (3) | First name of America's "P" (6) M's candy partner...

An appealing interlude... Recent in youth, I earned some praise On time has passed, those were the days So now I'm idle E're by myself Seeking a saviour, on any shelf Some say I'm hard, but that isn't true Though I require, some work from you Oodles of hints No hint was s...