- New Sloped wall piece: a half-block triangle in any wall material, at half a wall's cost. Dragging walls or slopes at about 45° lays a diagonal line; the drag picks the slope's orientation and T flips or turns it. - Each slope fills one cell past its corner, so a diagonal run is sealed against grains and water. - New test/t_slopes.js: a slope funnel passes 400/400 sand (square steps 379/400). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>