Degenerations of Pascal lines

Let $${\mathcal {K}}$$ denote a nonsingular conic in the projective plane. Pascal’s theorem says that, given six distinct points A, B, C, D, E, F on , three intersection $$AE \cap BF, AD CF, BD CE$$ are collinear. The line containing them is called Pascal of sextuple. However, this construction may fail when some come together. In paper, we find indeterminacy locus where not well-defined and then use blow-ups along polydiagonals to define it. We analyse geometry Pascals these degenerate cases. Finally offer remarks about other geometric elements hexagrammum mysticum.