I'm reading CLRS Section
33.4 Finding the closest pair of points. At exercise
33.4-2 they say
Show that it actually suffices to check only the points in the 5 array positions following each point in the array Y'
But I'm getting 4 array positions following each point in the array Y' will be suffice to check. See the fig below
Which possibility I'm missing. Can anybody point it out.