Interaction Analysis on Red Spinach Morphological Features. The morphological data for 2-compound combinations were used to generate response surfaces that describe the interactions at different concentration ratios (N = 2-6). The dotted black box represents the original range of concentrations (0 – Level 2) tested. The unit for SWE is % v/v. The heatmaps of each response surface are displayed in Figure 10. Individual replicates and interaction maps for each response surface are illustrated in a scatterplot in Figure 11 and in Figure 14, respectively.