Joint distribution of intrinsic colors, observed colors, and velocities along with the intrinsic color locus for each color for the gamma-constant simulation (Section 4.2). This simulation assumes a gamma distribution of velocities and constant mean intrinsic colors independent from velocities (black solid line) with some intrinsic scatter (black dashed lines). The observed colors (red points) are generated from the intrinsic colors (blue points) by adding reddening due to a random dust extinction drawn from an exponential distribution, A_V ~ Expon(τ = 0.3 mag), and by adding random measurement error.