@@ -171,7 +171,7 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
   <a href="showcase/planet-rover/"><img src="showcase/planet-rover/preview.webp" width="24%" alt="Planet rover: a six-wheeled rocker-bogie rover with gold-foil sides, a camera mast, a dish antenna and a finned power unit, its arm drilling a boulder on red-grey regolith" /></a>
   <a href="showcase/traffic-cones/"><img src="showcase/traffic-cones/preview.webp" width="24%" alt="Traffic cones: orange cones with white reflective collars on a patch of asphalt with a worn white line, three standing in a row, three nested in a stack and one knocked over showing its open base, before a striped A-frame barricade with an amber warning lamp" /></a>
   <a href="showcase/mushroom-stump/"><img src="showcase/mushroom-stump/preview.webp" width="24%" alt="Mushroom stump: a sawn tree stump with a stepped felling cut and torn hinge fibres, peeled bark with curling flakes, moss, banded shelf fungi, honey mushroom clusters, red fly agarics, ferns and fallen leaves on a sloping soil disc" /></a>
-  <a href="showcase/go-kart/"><img src="showcase/go-kart/preview.webp" width="24%" alt="Go-kart: yellow go-kart on a patch of track asphalt before a red and white kerb: bent red tube chassis, black seat, finned engine with chain to the rear axle, slick tyres on silver rims." /></a>
+  <a href="showcase/go-kart/"><img src="showcase/go-kart/preview.webp" width="24%" alt="Go-kart: blue go-kart on a patch of track asphalt before a red and white kerb: moulded nose, side pods and a front panel with a white plate, red tube chassis, black seat, finned engine." /></a>
   <a href="showcase/broadleaf-oak/"><img src="showcase/broadleaf-oak/preview.webp" width="24%" alt="Broadleaf oak: a mature oak with a massive buttressed trunk and crooked limbs reaching out under a broad dome of lumpy dark-green leaf cushions, on a grassy mound with roots, tufts and fallen leaves" /></a>
   <a href="showcase/farm-tractor/"><img src="showcase/farm-tractor/preview.webp" width="24%" alt="Farm tractor: green farm tractor in muddy ruts beside a puddle: long bonnet, barred grille, rusty exhaust stack, big lugged rear tyres on cream rims with weights, small ribbed fronts." /></a>
   <a href="showcase/fern-mossy-rock/"><img src="showcase/fern-mossy-rock/preview.webp" width="24%" alt="Fern and mossy rock: a male fern's arching crown of cut fronds and fiddleheads beside a split gritstone boulder with flat broken faces, lobed moss cushions and a small fern in its crack, on a soil bank with beech litter" /></a>
@@ -298,7 +298,7 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
 
 [`mushroom-stump`](showcase/mushroom-stump/) — the seventh `nature` piece: procedural felled-tree stump on a sloping forest-floor soil disc (one furrowed lathe about a plumb axis flaring through five buttresses into the ground, plated bark peeled in two patches to grey sapwood under a ragged torn lip with curling flakes, a felling top with weathered growth rings round a dark heartwood, radial drying checks notching the rim, the undercut floor a step under the back cut and a low band of torn hinge fibres along the step, five surface roots lying in the soil and diving into it, thin moss cushions laid on the furrowed bark on the shaded flank and in the root crotches, two tiers of turkey-tail brackets, three fly agarics with warted caps, pleated gills, a volva and a hanging skirt, two clusters of ringed honey fungus out of a root and the stump's foot, fallen leaves, bipinnate ferns, twigs and pebbles), whose foot sealed in the soil all round, caps seated on their stipes, level cut and stated size, roots bedded along their run, stipes rooted in their soil or wood, brackets rooted in the bark, moss on up- and shade-facing surfaces, ground cover joined to the soil, the felling step and low hinge band, the torn bark standing over the sapwood with its flakes rooted, and the moss a thin shell on the bark are recomputed from the mesh, through the same pipeline. `--perch-stump` exits 17 on the stump sealed all round, `--float-caps` 18 on every cap seated on its stipe, `--tilt-cut` and `--fat-stump` 19 on the level cut and stated size, `--arch-roots` 20 on the roots bedded, `--float-mushrooms` 21 on every stipe rooted in its host, `--float-brackets` 22 on the brackets rooted in the bark, `--sunny-moss` 23 on moss facing up or into the shade, `--float-cover` 24 on the ground cover joined to the soil, `--flat-felling` and `--tall-hinge` 25 on the felling step and low hinge band, `--flush-peel` and `--float-flakes` 26 on the torn bark over the sapwood and its flakes rooted, `--slab-moss` 27 on the moss laid on the bark, while the envelope holds.
 
-[`go-kart`](showcase/go-kart/) — the eighth `vehicles` piece: procedural rental go-kart on a patch of kart-track asphalt against a red and white kerb (a 30 mm tube chassis whose main loop is one bar swept round every bend, cross tubes ending inside the rails with welded gussets, bearing hangers and kingpin C-brackets; spindles on kingpin bolts with 14° caster; a three-spoke wheel on a raked column in a bushing, a steering plate and two tie rods on rod-end eyes; a bolted nose, side pods on nerf bars and a curved front panel; a moulded seat on stays, a floor tray, two pedals, a strapped fuel tank with its line and a lead ballast block; a finned four-stroke clamped to the right rail with a pull-start, air-box and silencer, driving the live rear axle through a clutch, an 88-link chain solved to a whole number of pitches and a 60-tooth sprocket; bearing carriers, a brake disc and caliper; a tubular rear bumper; four loaded slicks on split rims with valve stems, the fronts narrower than the rears), whose tyres pressed into the asphalt in one plane, hubs and bearings coaxial with their axles, tie-rod eyes on their pins, tyre beads and chain seated, frame, bodywork and wheels mirrored at the stated wheelbase and tracks, caster, mass centre inside the support polygon and one connected assembly are recomputed from the mesh, through the same pipeline. `--float-tyre` exits 16 on every tyre grounded, `--cock-hub`, `--drop-bearing` and `--short-tierod` 17 on joint fit, `--sink-tyre` and `--lift-chain` 18 on the bead and chain seats, `--toe-wheel`, `--wide-track`, `--odd-frame` and `--no-caster` 19 on mirror, size and caster, `--aft-ballast` 20 on the stance, `--loose-ballast` 21 on one connected assembly, while the envelope holds.
+[`go-kart`](showcase/go-kart/) — the eighth `vehicles` piece: procedural rental go-kart on a patch of kart-track asphalt against a red and white kerb (a 30 mm tube chassis whose main loop is one bar swept round every bend, cross tubes ending inside the rails with welded gussets, bearing hangers and kingpin C-brackets; spindles on kingpin bolts with 14° caster; a three-spoke wheel on a raked column in a bushing, a steering plate and two tie rods on rod-end eyes; blue moulded bodywork: a nose cone with a raised hump and lipped shoulders, pods with a crest, a ribbed deck and a groove, and a front panel leaning back from the hump with a white number plate, held by ten strap brackets welded to the tubes and bolted to the mouldings; a moulded seat on stays, a floor tray, two pedals, a brake master cylinder with its hose to the caliper and a throttle cable to the carburettor, a strapped fuel tank with its line and a lead ballast block; a finned four-stroke clamped to the right rail with a pull-start, air-box and silencer, driving the live rear axle through a clutch, an 88-link chain solved to a whole number of pitches and a 60-tooth sprocket; bearing carriers, a brake disc and caliper; a tubular rear bumper; four loaded slicks on split rims with valve stems, the fronts narrower than the rears), whose tyres pressed into the asphalt in one plane, hubs and bearings coaxial with their axles, tie-rod eyes on their pins, tyre beads and chain seated, frame, bodywork and wheels mirrored at the stated wheelbase and tracks, caster, mass centre inside the support polygon, one connected assembly and every bracket biting its tube and its moulding are recomputed from the mesh, through the same pipeline. `--float-tyre` exits 16 on every tyre grounded, `--cock-hub`, `--drop-bearing` and `--short-tierod` 17 on joint fit, `--sink-tyre` and `--lift-chain` 18 on the bead and chain seats, `--toe-wheel`, `--wide-track`, `--odd-frame` and `--no-caster` 19 on mirror, size and caster, `--aft-ballast` 20 on the stance, `--loose-ballast` 21 on one connected assembly, `--float-nose` 23 on the bodywork brackets, while the envelope holds.
 
 [`broadleaf-oak`](showcase/broadleaf-oak/) — the eighth `nature` piece: procedural mature, open-grown English oak on a grassy mound (a massive, short trunk with broad flutes and deep-furrowed bark plates flaring through seven buttresses into surface roots bedded in the soil, a low fork into five zig-zag scaffold limbs, the low ones reaching out sideways nearly level, that divide three more times into 155 tapered branches, each seated in its parent and narrowing past every junction by its child's area, a domed crown of 295 leaf-mass cushions — a hidden core on each carrier, 2075 faceted leaf clusters centred in the cores and shaded as billows by custom normals, 618 small lobed oak leaves on the outer clusters — dead twigs, acorns with scaly cups and glossy nuts hanging on stalks and lying in the grass among leaf litter, forked twigs and tufts), whose branch seats, da Vinci taper, nuts seated in their cups, plumb trunk and balanced crown, foot and roots sealed in the soil, cushions on their carriers, clusters in their cores and leaves in their clusters, acorns hung on their stalks and ground cover joined to the soil are recomputed from the mesh, through the same pipeline. `--float-branches` exits 17 on every branch seated in its parent, `--pop-nuts` 18 on every nut seated in its cup, `--lean-crown` 19 on plumb and balance, `--fat-twigs` 20 on the taper and area rule, `--perch-trunk` and `--arch-roots` 21 on the trunk and roots sealed in the soil, `--orphan-clump`, `--scatter-clusters` and `--shed-leaves` 22 on every cushion on its carrier, cluster in its core and leaf in its cluster, `--drop-acorns` 23 on the hanging acorns on their stalks, `--float-cover` 24 on the ground cover joined to the soil, while the envelope holds.