Asset Reuse
Not creating the same object over and over again has always been common practice for digital artists. If you've already modelled a particular element, let's say a model of a human figure, the chances are that you'll be better off re-using it and making a few tweaks the next time you need something like it. Although this can sometimes be seen as a form of laziness, it is a very important way of keeping the workload manageable. If it is done in the right way, it has other advantages as well. For example, it introduces a degree of consistency in style. Beacuse reuse can be applied not only to the geometry, but to the materials as well.
For open graphics, this is a big plus, because it makes it easier to research. Sometimes you can just find a scaled-up or rotated version of a sprite that has been reused. This opens up the bigger picture of what the 3D model used looked like originally.
With a little bit of guesswork, you may find that several RCT2 assets have been built using the same 3D elements.
The same human model is used for the "Roman Statue" and the "Horseman Statue".