Really happy to have fill up, overfill, and overflow working, despite introducing (and exposing) some issues along the way:

• Water needs to attempt to pass through itself / waterfalls not seeked through when seeking left / right
• fallbackCandidates reporting double numbers in the logs: 14, 19, 14, 19
• Water repeating messages forever even when there's no more water being created - likely an unclosed fallback candidates loop that is looking for an empty cell but not finding it:
  • canFillUp called on (16,17)
    
  • Cell above is not empty: water
  • canFillUp called on (16,18)
  • Cell above is not empty: water
  • canFillUp called on (16,19)
  • Cell above is not empty: water
• Water not reverting to OG logic after fill, overflow, fallback (as seen in debug logging)
• Water overflow and water fill should be able to co-routine so that water can fall down the side of the structure while the structures final row gets filled
• All 40 rows are being searched when looking for fallbackcandidates (and potentially otherwise?) even when logically it should be more efficient than that - water can only spawn above in a structureless situation - no need to seek 40 cells