Figure 4: Image showing a low redshift (closer) companion blending with a higher redshift (more distant) galaxy. We see the biased response to shear at a given redshift in the bottom panel, which changes our effective redshift distribution for our gravitational shear. Many of these blends put together will change our ensemble distribution, and distort our understanding of the underlying cosmology if we have too many blends and do not model this effect in our simulations. (Credit: DES Collaboration, MacCrann et al., 2021.)