Thinly slice lemons. Remove seeds. Alternate layers of lemon slices and sugar in a bowl. Allow mixture to sit for at least 20 minutes to macerate. (The longer it sits the easier it is to mash) Using a potato masher or the back of a wooden spoon, press the mixture well to release the juices. Add the water, pressing fruit until the liquid is well flavored. Pour liquid into a decorative pitcher filled with ice. Use some of the Lemon slices as a garnish if desired.