Trapdoors were quite straightforward to design after doors. Here are all trapdoors showcased here with their matching tree barks & doors counterparts.
You’ll notice I didn’t use full height on the POM (the POM effect is a tad shorter than the block depth). It’s a design decision, I thought full depth looked too overwhelming & the repeating pattern caused by POM was a bit off-putting. This level of POM is maybe not to scale, but feels much more natural.