In our representation, the similarity between two patches \(p_{i}\) and \(p_{j}\) can be assessed using simple metrics, such as the cosine similarity between their directions \(s_{ij}=\hat{u}_{i}\cdot\hat{u}_{j}\).  Based on known patterns of cortical variability, we hypothesized that our features would vary across the cortical sheet in a somewhat reproducible fashion across HVs.  To assess this, we defined patches as being in homotopic (same) or heterotopic (different) locations as defined by the standard surface mesh (Figure 1b),  and computed the cosine similarity between 1000 randomly sampled heterotopic patches and 1000 heterotopic patches across HVs.