Build a bridge from roads and beams on a budget so a loaded truck can cross the gap. Triangles stay rigid, overloaded members snap, and every level's clock is shorter.
Drag from a red anchor or any joint to a nearby dot to place a member; the Road and Beam buttons choose what you lay. Tap a member to remove it, ↶ undoes and ✕ clears everything. Once a road joins the two red anchors at the cliff edges, press ▶ Test to send the truck across before the level clock runs out.
Road ($20 per square of length) is the only thing the truck drives on, and no road piece may be steeper than 45°. Beams ($10 per square) are lighter and hold the road up. A member spans at most two squares in a straight line, or two squares one way and one the other, and a piece that would take you over the level's budget is refused. Joints sit on the dots of the grid; you cannot build inside the rock.
The bridge is a pin-jointed truss: every joint is a hinge, so only triangles keep their shape. A joint held by a single member, or only by members on one straight line, can swing, and the test shows the bridge as wobbly. Every member carries its own weight (road 1 t per square, beam 0.5 t) plus the truck. Road holds 80 t of pull or push and a beam 60 t, but a member longer than 1.5 squares buckles sooner when it is squeezed: a two-square member keeps 56% of its push strength and the long two-by-one diagonal 45%. If any member goes past its limit while the truck crosses, it snaps and the test fails. After a failed test the members are coloured from green (relaxed) to red (at the limit).
The gap is 2 squares on level 1 and grows by one square every two levels, up to 9. The truck weighs 10 t on level 1 and up to 1.2 t more each level, but never more than a fully braced grid of that level could carry. Each level is generated together with a solution the game has checked, and the budget is set from that solution's cost: 55% above it on level 1, 3 points less each level, and 12% above it from level 16 on. The clock is 120 seconds on level 1 and 3 seconds shorter on every level after, with no lower limit, so a run ends by level 40 at the latest. A failed test costs nothing but the seconds it takes. When the clock reaches zero the run ends and the result card shows the checked solution for that level.
Score: the number of levels cleared. Equal counts are ranked by the total time that was left on the clock, to a tenth of a second, at the moment you pressed Test on each level you cleared.
Give the road something to stand on. A road joint in mid-air has nothing under it, so the cheapest support is often a single beam down to a red anchor on the cliff face: it turns a long span into a short one for $14 to $22. Use every anchor the level offers before you build towers, and if there is a stone pier in the middle, brace the deck to it — it roughly halves the span the rest of the bridge has to carry.
Depth is strength. A truss works like a deep beam: the road and a chord one or two squares above or below it share the bending, and the deeper the triangle, the less each chord has to carry. A flat strip of road with short diagonals is cheap but fails first on wide gaps; lifting the top chord to two squares often lets you delete members instead of doubling them. Remember which side is squeezed. Under a truck the lower chord of a truss hung below the road is pulled, and the top chord of a truss built above it is pushed.
Put long members where they pull. A member longer than 1.5 squares loses push strength quickly — the long two-by-one diagonal holds only 45% when squeezed — but keeps its full 60 t (beam) or 80 t (road) in tension. So use the long diagonals as ties and keep the compressed members short; if a red member after a failed test is a long strut, split it with a joint and brace that joint rather than adding a second long strut beside it.
Test early, then trim. A failed test costs only the few seconds the truck takes, while the clock is the only thing that ends your run and every second left when you press Test counts towards breaking ties. Lay the road first, add the obvious triangles, test, and let the colours show you where the load really goes; green members are candidates to delete when you need budget elsewhere. The budget is at least 12% above a solution the game has already proven, so a bridge that leaves money unspent is perfectly fine — speed matters, savings do not.