Step 6: 3.5 leaf clovers, color variants, and "spades"
Some clovers (not very exciting, but pretty rare) have a mitten shaped leaflet due to conjoined leaves. You can tell they are conjoined by looking under the leaflet and noticing that it contains two stems (see below). Even rarer: sometimes part of conjoined leaf breaks off, with a little leaf sticking like a "thumb" off the mitten (sorry, no pic)
Some clovers will also have a "rust color". This is probably due to an inability of this clover to produce green chlorophyll in the leaflets, showing the less dominant red, yellow, or brown hues, much like how leaves turn colors in fall. Unlike deciduous plants, however, I've noticed this discoloration through out the year.
"Spade Leafed" clovers are a mystery to me. These clovers exhibit a strage shape of each leaf which reminds me of the shape of a spade. At first i thought it was due to insects, but the pattern is too perfect and insects too hungry to always produce this shape. Must be a mutant!(?) Weird...