Say the fence rule without overloading pin, and file the twice-drawn table

CHANGELOG.md

@@ -19,8 +19,8 @@ replacement, and each removed path, column or flag.
   table above it, a table whose format or cell references its own family, and,
   within one render and draw group, a path drawing a table another path selects a
   row of, or two paths pinning different rows of one table. Two reads are held to one
-  draw only where a render can pin both their rows: a path read pins a row's ancestors
+  draw only where both their rows can render together: a path read pins a row's
-  with it, while a table read whole draws a row and pins none.
+  ancestors with it, while a table read whole draws a row and pins none.
 - `New` refuses a root choice of templates sharing one format and one set of string
   fields, naming the rows TSV to write instead.
 - `misc.territory`, `misc.currency`, `misc.language`, `misc.httpstatus` and

README.md

@@ -1141,8 +1141,8 @@ the Development section below, and who ships a register the four above then draw
   row and a cell in another never meet, and each may select its own row of another
   table; the cells of one row, and whatever they reach, do meet, and so does the
   format beside them. The rule the fence applies is that two reads meet unless they
-  sit in two rows of one table, or in rows no render pins at once: a path read pins a
+  sit in two rows of one table, or in rows that never render together: a path read
-  row's ancestors with it, while a table read whole draws a row and pins none. A
+  pins a row's ancestors with it, while a table read whole draws a row and pins none. A
   choice's items get no such treatment yet: two items selecting different rows
   are still refused.
 - **A table never reaches its own family, by any route.** A `repeat` iteration and a

draw.go

@@ -297,7 +297,7 @@ type drawAt struct {
 	group string
 	route drawRoute
 	alt   rowSet
-	drawn *table
+	drawn *table // only that table's own cells read it, which the own-family fence is what keeps true, so the visit keys leave it out
 }
 
 // rowSet is the rows a walk entered, one per table: only one row of a table renders, so reads in
@@ -404,7 +404,9 @@ func (w *drawWalk) walk(n node, at drawAt) {
 			if at.alt.excludes(cell) {
 				continue
 			}
-			w.edge(n, e, drawAt{at.group, at.route, at.alt.enter(cell.cellOf, cell.cellRow, cell.cellOf != at.drawn), at.drawn})
+			in := at
+			in.alt = at.alt.enter(cell.cellOf, cell.cellRow, cell.cellOf != at.drawn)
+			w.edge(n, e, in)
 			continue
 		}
 		w.edge(n, e, at)

todo.md

@@ -153,6 +153,10 @@ by a `data-import/` script, as README goal 12 asks.
 
 ### Library and CLI
 
+- Hold two whole reads of one table to one row, or refuse the pair: `{/region}|{/region}`
+  draws a row for each read, so cells of two rows render together while the fence counts
+  them alternatives and compares neither — a bare `{/addr}` in one row beside
+  `{/addr.city}` in another is the overlap it refuses everywhere else.
 - Name a spelling that works when a row selector misses: `misc.protocol[tcp]`,
   `misc.httpmethod[get]` and `misc.territory[se]` all answer "no row … has key or name"
   and stop there, where a case-insensitive match could name the row that exists, and a