I've been spending a lot of time on level 16, and plenty of a-ha moments that all fell short. Any clue ?
(ROT13) V guvax V unir svtherq bhg gung lbh fubhyq svaq n jnl gb npgvingr gur yvsg gb tb onpx ba gbc yriry hfvat gur 4 2-pryy oybpxf, ohg pna'g svaq n jnl.
Viewing post in Isaac and the Conservation of Mass comments
That’s generally the right idea.
Hint 1: Gel gb svaq n pbasvthengvba bs gur wryyvrf juvpu ernpurf sebz n pryy arkg gb gur ybjre yvsg gb gur hccre yvsg.
Hint 2: Abgr gung ng gur cbvag jurer lbhe pbagencgvba ernpurf gur hccre yvsg, vg’f bxnl sbe cnegf bs vg gb qebc gb gur tebhaq sybbe (gurl whfg unir gb or fhccbegrq ba gur cerivbhf ghea).
Hint 3: Erzrzore fbzr bs gur zber fhecevfvat zrpunavpf lbh’ir yrnearq guebhtubhg gur tnzr.