A siege tower at the walls.
Siege towers are vehicles in Movecraft which can travel along the land at a slow pace.
Minimum blocks: 150
Maximum blocks: 1000
Top Speed: 1 m/s
Blocks allowed: Only wooden, wood-based, and wool blocks.
To create a siege tower, create a sign facing forward (to the front of the tower), and type "siegetower" in the first line. Drive it like you normally would a ship, using a compass to steer.