Spirals

문제

A spiral of numbers can start and end with any positive integers less than $100100$. Write a program which will accept two positive integers $xx$ and $yy$ as input, and output a list of numbers from $xx$ to $yy$ inclusive, shown in a spiral. You may assume that the end value is greater than or equal to the start value.

A spiral starts with the first number in the centre. The next number appears immediately below the first number. The spiral continues with the numbers increasing in a counter-clockwise direction until the last number is printed.