Trefoil is the friendly door into the fan family. Before a single card reaches the table the four aces are lifted out and placed on their foundations, and the remaining forty-eight deal into sixteen neat fans of three. Nothing about the building is relaxed — it still builds down strictly by suit, one card at a time, and an emptied fan is gone for good — but starting with every foundation open changes the opening from a search into a plan.
Do not bank a two just because you can. With the aces already up, twos and threes are playable almost immediately, and that is the trap. Sending a two to its foundation while the matching three sits buried under a king strands the whole suit. Look at what covers the next card before you play the current one.
Empty the shallow fans, not the deep ones. A fan you clear is a fan you can never use again, so the ones worth clearing are the ones that were nearly useless anyway. A three-card fan whose exposed card is a low spade is a resource; a fan already down to one awkward king is not.
Spend the first redeal early rather than late. Players hoard reshuffles and then use them on a board with eight cards left, where a shuffle changes almost nothing. A redeal is worth most while there are still enough cards for the shuffle to rearrange.
Read the whole board before every move. Suit-only building means most cards have exactly one legal host anywhere on the table. Finding it is not a matter of scanning the nearest fan — it is a matter of knowing where that suit's next card sits.
The fan family — La Belle Lucie and its relatives — is defined by what it withholds. There is no stock, no reserve, no free cell and no run move; one card per fan is available, and a fan you empty is gone. That makes it the purest "which one do I open next" puzzle in patience, and it also makes it the family where a single rule change is felt hardest. Trefoil turns the gentlest dial: it starts the foundations for you. Super Flower Garden turns a much larger one by letting the tableau build on any suit. Shamrocks goes the other way, capping every fan at three cards and taking the redeals away entirely.
Trefoil runs in your browser — free, no download, no sign-up. Install it as an app on your phone or computer and it works offline. You get unlimited undo (the redeal can be taken back too), a hint button that names a legal move, statistics that track your wins and times, and seeded deals: every game has a seed you can replay, so a board you enjoyed (or lost) can be played again exactly.