Jungle takes Blue Moon's board — four rows of fourteen, every card face up, four gaps to work with — and removes the suit from the fill rule. Any card one rank higher than the card to a gap's left will fit, whatever it is. That sounds like a gift and it is only half of one, because the win condition never changed: a row is finished only when it reads Ace to King in a single suit. So a row you can fill in seconds is very often a row you will have to pull apart again. Free in your browser, no sign-up.
Goal: make every row read Ace to King in a single suit.
Legal moves are everywhere. Useful ones are not, and telling them apart is the entire game.
Jungle is registered in the PySol Fan Club collection as a Blue Moon variant, and its class does two things: swap the row stack for one whose accept rule drops the suit comparison, and cut the redeals from two to one. Everything else — the four rows of fourteen, the Aces seated at the head of each row, the leftmost gap that takes an Ace — is inherited unchanged.
The pairing of a loosened build with an unchanged goal is a shape this catalogue keeps meeting. Black Widow lets any descending run travel in the Spider family while still demanding single-suit sets; KingCell builds suit-blind in FreeCell while its foundations still take suits. In each case the freedom is real and it does not shorten the game — it moves the difficulty from finding a move to choosing one.
For the strict version of this board, play Blue Moon. For the same grid with the rule loosened the other way — same suit, any higher rank — try Spaces and Aces. For the family's classic twelve-card rows with the Aces out of play entirely, play Gaps.
One honest note on difficulty. No published win rate for Jungle that we can find carries a method or a sample size, so this page quotes none. Structurally the loose fill and the single redeal pull against each other, and the result is a game that rarely stalls early and often cannot be finished.