T1 and T2

Could Thing 1 and Thing 2 be mirror-image twins?  This is quite possible!  We know that the boys are monozygotic (twins that are formed from a single fertilized egg).  A lot of people call these kind of twins identical.  However, mirror-image twins happen in about 25% of identical twins.

With mirror-image twins the split of the egg occurs late - more than a week after conception - the twins can develop reverse asymmetric features. This term is not really a type of twin, just a way to describe their physical features. For example, they may be right- and left-handed, have birthmarks on opposite sides of their body, or have hair whorls that swirl in opposite directions. In theory, if the twins faced each other, they would appear to be exact reflections of each other.

Thing 1 and Thing 2 don't exhibit these characteristics.  BUT, the other day I noticed an interesting fact about them.  One can whistle forwards and the other backwards!  Yup!  Is that not the coolest?  One boy whistles a tune blowing air OUT...and the other has to suck IN to make a whistling noise.  If that doesn't constitute mirror-image twins, then I don't know what would!