class Centimeter < Measurement
  abbreviation :cm
  units :cm
  coerce :m, :*, 100
  coerce :km, :*, 100*1000
  coerce :mm, :/, 10
end

class Meter < Measurement
  abbreviation :m
  units :m
  coerce :cm, :/, 100
  coerce :km, :*, 1000
  coerce :mm, :/, 100*10
end

class Kilometer < Measurement
  abbreviation :km
  units :km
  coerce :m, :/, 1000
  coerce :cm, :/, 1000*100
  coerce :mm, :/, 1000*100*10
end