You are standing in the very corner of a 10 X 10 grid of dots. How many different ways are there to get to the opposite corner of the grid? You must travel through every node once, and only once. You cannot travel diagonally, and you may not go outside of the overall perimeter.
When we metnion the 'corner', we could refer the very edge of the grids of dots. It is just like when there is a piece of wall in an area and somebody calls you to stand at the corner of the wall, it could refer to any edge of the wall and it does not necessarily refers to the place where the two lines are met.
Even if there must be a restriction to the corner where one horizontal line & one vertical line are met, there are still numerous solutions. I will prove it to you.
Thanks.