ink of penetration to mark hidden objects on opened map;
augmented exploration map to structures of various types (depends on the ink color);
Warnings:
Don't generate too much maps of rare places at a time. Once place detected it excludes its reference from further search. So a next structure can be enormously far away: the average distance between Mansion for example is 5k blocks);
Notes:
each potion color refers to particular structure type (each next map colored with the same color refers to another structure of the same type);
several potion colors can reference to the same structure or feature type (depends on the world seed);
exploration map can disappear on opening if target structure type doesn't belong to current dimension (try the same color in neither or end);
