by Serhiy Grabarchuk Jr
What number from among the suggested ones should replace the question mark to complete the sequence?
Moving up and right, each number represents the number of days in year’s seasons, starting with Winter’s 90 days in the lower left circle. The circle with the question mark is also Winter. It is the 4th Winter compared to the lower left one. Every 4th year is a leap one with 29 days in February, resulting in 91 days in the leap year’s Winter.