, long vine construction.

Construction		Source		Result
	0	pit	#	palisade wall
			|	rope and pulley
	0	pit	+	palisade gate
	0	pit	o	palisade wall with embrasure
			#	bale of hay
		is:DIGGABLE
	.	rock floor
	#	solid rock
	~	deep water	8	pontoon bridge
	~	flowing deep water	8	river bridge