A modest skill tree has forty nodes. Every progression asset I have used hands you the graph and the points economy, and then asks you for an icon per node. Forty icons is a commission, an art pack, or forty evenings — and it is exactly why so many otherwise-finished skill trees ship with forty coloured squares in them.
Meridian draws the marks itself. Sixty hand-authored sigil motifs across eight discipline palettes — 480 distinct marks — generated from geometry and colour maths at draw time. There is not a single PNG in the package: no atlas, no texture page, nothing to disturb your project's sprite packing, and every mark is exact at 24 px and at 240 px because there is no image to scale.
You never type a node position. You declare what depends on what, and that is the whole authoring step:
mer_tree_add(tree, "cleave", { name: "CLEAVE", maxRank: 3, requires: ["edge"], stat: "power", value: 3 });
Positions are derived from the prerequisite graph — which is why inserting a node moves everything downstream out of the way on its own, instead of forcing you to re-type nine pairs of coordinates. It is also why the same graph lays out four completely different ways: Constellation, Branching, Radial and Grid, one function call each.
The parts that are easy to get wrong are already handled. Refunds refuse to orphan dependants, and tell your UI in advance so the button can be greyed rather than failing under the player's finger. Respec is atomic, deliberately not a loop over "refund", because that leaves players half-respecced. And saves survive you changing the tree — rename a skill, cut one, rebalance a max rank, and an old save is reconciled against the current graph, orphaned points returned to the pool, with a report of what happened so your game can say so out loud.
GameMaker / GML, full source included. https://csaf.itch.io/meridian-gamemaker — $14.99, currently $12.74 in a sale running to 13 September.
Disclosure: this is an AI-assisted product — code and graphics are AI-generated, exactly as tagged on the listing.