The retaining wall package is a set of 16×16 base walls that can be used to cover raised platforms. The design uses part 71771 curved slopes which normally come with the new road plate system. The main goal of this design is to utilize the piece and make the retaining wall more cost effective and accessible for LEGO city builders.
The package comes with the following instructions & parts lists:
retaining wall with stairs
retaining wall with tunnel
retaining wall corner
bench & plant box accessories
To better understand the design, you may watch this video: