Line one is simply there to get things going.
Line two is line eleven when up-ended.
Line three’s to gain a bit more ground for hoeing.
Line four rhymes with line two - that’s what’s intended.
Line five gives you a sudden spiteful zap.
Line six’s a dozen that’s been split in two.
Line seven’s such an awful load of crap,
Line eight’s dead serious - vice versa, too.
Line nine repeats a now familiar ditty.
Line ten could turn out quite a disillusion
Line eleven’s eleventh - more’s the pity.
Line twelve’s a nothing’s ultimate conclusion.