Wall drags at 45° lay slopes; diagonal tubes drawn as one pipe; no side arrow on drag ghosts (t35, t36)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/agent-log.md

@@ -4,6 +4,18 @@ What agents have done, newest first. Add an entry for every piece of work: the d
 note or request it was for, what changed, the files touched, the tests run, and anything left
 open or not verified. Keep each entry short; the git history has the details.
 
+## 2026-10-25: t35/t36 follow-ups: wall drags make slopes, diagonal tube art (Claude Code, Codex)
+
+- Wall piece: a diagonal drag lays slopes (`pieceCode`/`turnSlope` in `src/ui/selection.js`), T flips
+  a drag or cycles square and four corners for one block; the Sloped wall piece is gone from the
+  menu, slope codes map to the wall piece (`src/sim/pieces.js`); old slope saves load
+  (`test/fixtures/slopes-v2.json.gz`).
+- Diagonal tubes draw as one continuous 45° pipe in both looks, overhanging empty cells at joints
+  (`src/render/world.js`, `smooth-shaders.js`). Drag ghosts lost the long side arrow; each ghost
+  block keeps its own chevron (`src/ui/previews.js`). The owner found the diagonal still meets
+  straight tubes off-centre; an elbow fix follows.
+- `test/t_slopes.js`, `t_diag_tubes.js`, `play.py`; `run_all.py --browser` ALL PASSED.
+
 ## 2026-10-25: t37 follow-up: grains on built things cast no shadows (Claude Code, Codex)
 
 - The owner saw a flickering shadow under a grinder fed by a stream: grains resting on its