They kind of tongue and groove almost one into each other.

一颗凸起进入凹下的那颗这样上下相扣。

The lintels were slotted together using tongue and groove joints, usually only found in woodworking.

门楣用榫舌和凹槽连接在一起，这种（方式）通常只会在木工艺中发现。