  We present a simple derivation of the Lorentz transformations for the
space-time coordinates of the same event. It is based on the relative character
of length and time interval as measured by observes in relative motion. We
begin by accepting that the relative motion modifies in some particular way the
result of these measurements. However we do not postulate the character of this
distortion i.e. whatever it is dilation or contraction. The formulas accounting
for length contraction, time dilation and Doppler shift are a byproduct of this
derivation.
