An object is extruded to have the form of a cage, the cage defined by spokes corresponding to several extrudate streams. The spokes bound a hollow interior and extend between opposed hub regions where the spokes are fused together. In manufacturing the objects, ceramic material is extruded through multiple dies arrayed around an extrusion axis, the dies mounted to permit controlled movement of the dies during the course of extrusion to vary the position of extrudate streams exiting the dies.

Provided is a mouthpiece for an extruder provided at an extruder extruding a flowable molding material, including: a molding material flow passage; a molding material extrusion port formed at a front end of the molding material flow passage; and one or plural flow resistance members provided to advance into and withdraw from the molding material flow passage, the advancing and the withdrawing being performed by an operation at the outside of the mouthpiece for the extruder.

An object is extruded to have the form of a cage, the cage defined by spokes corresponding to several extrudate streams. The spokes bound a hollow interior and extend between opposed hub regions where the spokes are fused together. In manufacturing the objects, ceramic material is extruded through multiple dies arrayed around an extrusion axis, the dies mounted to permit controlled movement of the dies during the course of extrusion to vary the position of extrudate streams exiting the dies.

An apparatus for making and depositing bricks includes a nozzle having an inlet opening, an outlet opening, and a plurality of walls surrounding the outlet opening. At least one of the walls is configured to retract relative to the other walls. When a first brick is deposited, all of the nozzle walls are in the extended position. When subsequent bricks are deposited, one or more of the nozzle walls are retracted so that the form for the subsequent bricks is provided by the walls that are in the extended position and the sides of the already-deposited bricks. In this manner, the nozzle is configured to deposit the bricks directly adjacent to each other without any space or intervening material between them. The bricks may be deposited in a heated state and they meld together as they cool. The nozzle is particularly advantageous for paving autonomously in otherwise inaccessible locations, such as surfaces on the moon or other planets.