I found a really interesting workbook that calculates the shortest distance from a start cell to an end cell. It is all made with excel formulas, not a single vba line! It uses a grid of 12 by 12 cells and the workbook is 11 MB.
I wanted to see if it was possible to make a bigger grid so I made a grid of 30 by 30 cells. The workbook quickly grew to 60 MB and there are 8 sheets. The maze is built by entering 1 for a wall cell. Conditional formatting then makes the cell black.
The animation below shows me deleting walls and the workbook instantly finds a new shorter path.
I also tried making an even larger grid, 65 x 65 but the workbook became too big. You can see my labyrinth here.
I guess this is a task for vba but that will be another post. [UPDATE] The follow up post is here: Finding the shortest path – A * pathfinding