This happens because the mirror is parallel with the plane of symmetry.

这是因为镜子与对称平面平行。

He liked to go from room to room, as in a gallery of parallel mirrors, until Prudencio Aguilar would touch him on the shoulder.

他喜欢从一个房间走到另一个房间，就像在平行镜子的画廊里一样，直到普鲁登西奥·阿吉拉尔 (Prudencio Aguilar) 碰了碰他的肩膀。