\magnification=\magstep0

$$
  {\rm distance\ } = \sqrt{ {(\rm North\  position)}^2 +
                            {(\rm East\ position)}^2 }
$$

$$
\vbox{
\halign{ \hfil # \hfil \quad & \quad \hfil # \hfil \cr
 \bf {Parable} & \bf{Special Relativity} \cr
\cr
 North measured in miles  & Time measured in seconds \cr
 East measured in feet    & Distance measured in meters \cr
 Conversion $k = 5280$ feet/mile & Conversion $c = 2.99792458 \times 10^8$ m/s \cr
\cr
 $N({\rm feet}) = k N({\rm miles})$ & $t({\rm m}) = ct({\rm s})$ \cr
 $E({\rm miles)} = N({\rm feet}) / k$ & $t({\rm s}) = t({\rm m}) / c$ \cr
\cr
 North interval $\Delta N = N_2 - N_1$ & Space interval $\Delta x = x_2 - x_1$ \cr
 East interval $\Delta E = E_2 - E_1$ & Time interval $\Delta t = t_2 - t_1$ \cr
\cr
 $({\rm Displacement\ Interval})^2 = (k \Delta N)^2 + (\Delta E)^2$ &
    $({\rm SpaceTime\ Interval})^2 = (c \Delta t)^2 - (\Delta x)^2$  \cr
 $({\rm Displacement\ Interval})^2 = (\Delta N)^2 + (\Delta E)^2$ &
    $({\rm SpaceTime\ Interval})^2 = (\Delta t)^2 - (\Delta x)^2$  \cr
}
}
$$

\bye
