Building blocks with similar P(active) are close to each other in projections of chemical space. We hypothesize that by the similar property principle, 21 building blocks that are similar to each other will have similar P(active) values. In this study, we elect to use a combination of 3D shape and color Tanimoto, otherwise known as Tanimoto combo as our similarity metric. For each position, we calculate the Tanimoto combo scores between all building blocks and transform these scores into 2D coordinates via Uniform Manifold Approximation and Projection (UMAP), a dimensionality reduction technique (see Section 4.5). Using the UMAP coordinates, we create an approximation of chemical space, where each building block is represented by a point and the Euclidean distance between points is inversely proportional to the chemical similarity of the respective building blocks (Figure ). We emphasize that no information regarding the P(active) value of building blocks is introduced in this process.