Picross is a logic puzzle where you must discover which grid cells are filled in and which are blank according to numbers at the side of the grid. You may know Picross puzzles as Nonograms, Griddlers, or Paint by Numbers. They are all names for the same game.
Enable snaps on Kubuntu and install Neverbore Picross
Snaps are applications packaged with all their dependencies to run on all popular Linux distributions from a single build. They update automatically and roll back gracefully.
Snaps are discoverable and installable from the Snap Store, an app store with an audience of millions.