Graphical progressive fill

[Ferhat Kurtulmuş]

On Sunday, 11 December 2022 at 06:50:44 UTC, Joel wrote:
> I've been trying to fill in areas with a colour but can't work 
> it out. I want something like the effect where it fills with 
> diamonds. Not all at once but building up in the main program 
> loop.
>
> ########
> #              #
> #              #
> #      #      #
> #              #
> #              #
> ########
>
> ########
> #              #
> #      #      #
> #   ###    #
> #      #      #
> #              #
> ########
>
> ########
> #        #     #
> #     ###    #
> #  ##### #
> #     ###   #
> #        #     #
> ########

https://rosettacode.org/wiki/Bitmap/Flood_fill