▁called ▁a ▁d ith is ▁dou bling . ▁ ▁Following ▁the ▁si ub hal ▁or ▁d ith is ▁variation ▁are ▁other ▁more ▁complex ▁emb ell ish ments . ▁ ▁The ▁G ael ic ▁names ▁of ▁these ▁type ▁movements ▁are : ▁ ▁le um lu ath , ▁ta or lu ath , ▁and ▁cr ù n lu ath . ▁In ▁almost ▁all ▁p ib ro ch ▁in ▁which ▁these ▁later ▁movements ▁are ▁found , ▁the ▁variations ▁are ▁played ▁first ▁as ▁a ▁sing ling ▁and ▁then ▁as ▁a ▁dou bling ▁and ▁with ▁a ▁slightly ▁increased ▁tempo . ▁ ▁However , ▁not ▁all ▁p ib ro chs ▁will ▁include ▁all ▁or ▁even ▁any ▁of ▁these ▁movements ▁but ▁instead ▁use ▁variations ▁that ▁are ▁de emed ▁to ▁be ▁irregular . ▁ ▁In ▁addition ▁the ▁theme ▁will ▁usually ▁have ▁one ▁of ▁several ▁internal ▁structures ▁for ▁the ▁ordering ▁of ▁its ▁musical ▁phr ases . ▁These ▁are ▁usually ▁class ified ▁as ▁follows : ▁ ▁Primary ▁– ▁The ▁theme ▁or ▁ground ▁is ▁composed ▁of ▁two ▁two - bar ▁phr ases , ▁A ▁and ▁B , ▁played ▁in ▁the ▁following ▁order : ▁A AB ▁A BB ▁AB ▁Second ary ▁– ▁The ▁theme ▁or ▁ground ▁is ▁composed ▁of ▁four ▁phr ases , ▁with ▁A ▁and ▁B ▁being ▁one - bar ▁phr ases ▁and ▁C ▁and ▁D ▁being ▁two - bar ▁phr ases , ▁and ▁played ▁in ▁the ▁following ▁order : ▁ABC D ▁C B AD ▁CD ▁T ert i ary ▁– ▁A ▁relative ▁of ▁Primary ▁P ib ro ch , ▁with ▁three ▁two -