Related? https://www.t3x.org/files/floodfill.pdf

Basic interpreter for the code:

https://www.t3x.org/nmhbasic/index.html

To compile it:

       unzip nmhbas3_32.zip
       cc  -O2 -DEXTRA -o tcvm tcvm.c
       ./tcvm basic 

To run some basic programs:

      ./tcvm basic maze.bas
     #3 = maze.bas
     load #3
       OK
     run

Exit to your OS:

     system

OK, let's run the floodfill example from the PDF:

      ./tcvm basic flood.bas
      #3 = flood.bas
      load #3
       ok
       run