Pairing
Pairing[seqA, seqB]⟹pairs
returns all possible pairings of seqA and seqB.
Pairing[{seqA,intervalA, seqB]⟹pairs
returns only pairs touching some part of intervalA on seqA.
Pairing[seqA, {seqB,intervalB}]⟹pairs
returns only pairs touching some part of intervalB on seqB.
Pairing[{seqA,intervalA, {seqB,intervalB}]⟹pairs
returns only pairs touching some both part of intervalA on seqA and part of intervalB on seqB.


