The metric-equation's single map-frame (top) can facilitate many useful quantitative insights before invoking the Lorentz-transform's "pair" of framesP. Fraundorf (2011/2012) "Metric-first & entropy-first surprises", arXiv:1106.4698 ., each with their own yardsticks and synchronized-clocks (bottom). The time-dilation and length-contraction effects depicted for the green moving map-frame at bottom, which use simultaneity defined by the more colorful stationary map-frame, correspond to a proper-velocity dx/d"τ" of 1 , a Lorentz factor dt/d"τ" of Sqrt, or a coordinate-velocity dx/dt of 1/Sqrt .