Length 4, number of unique variants is 16.
cctt	[cctt,cctt,cctt,cctt]
ccrr	[ccll,ccrr,ccrr,ccll]
cttc	[cttc,cttc,cttc,cttc]
crrc	[cllc,cllc,crrc,crrc]
cctr	[cctl,cctr,cctr,cctl]
cttt	[cttt,cttt,cttt,cttt]
ctrr	[ctll,ctrr,ctrr,ctll]
ctct	[ctct,ctct,ctct,ctct]
cttr	[cttl,cttr,cttr,cttl]
crrr	[clll,crrr,crrr,clll]
ctcr	[ctcl,ctcr,ctcr,ctcl]
crct	[clct,clct,crct,crct]
crcr	[clcl,clcr,crcr,crcl]
ccrc	[clcc,cclc,crcc,ccrc]
cctc	[ctcc,cctc,ctcc,cctc]
ctrc	[ctlc,ctlc,ctrc,ctrc]