Total integrated bispectrum defined in Eq. (66) as a cumulative sum over orthonormal modal coefficients (upper panel) and over multipoles up to a given ℓ (lower panel). Above, the relative quantity is plotted, where is the mean obtained from 200 CMB Gaussian maps with the standard deviation shown as the red line. Below the square of the bispectrum is integrated over the tetrapyd out to ℓ and its significance plotted relative to the Gaussian standard deviation (1σ red line). A hybrid polynomial basis n_max = 600 is employed in the signal-dominated region ℓ ≤ 1500.