  A tower is a sequence of simplicial complexes connected by simplicial maps.
We show how to compute a filtration, a sequence of nested simplicial complexes,
with the same persistent barcode as the tower. Our approach is based on the
coning strategy by Dey et al. (SoCG 2014). We show that a variant of this
approach yields a filtration that is asymptotically only marginally larger than
the tower and can be efficiently computed by a streaming algorithm, both in
theory and in practice. Furthermore, we show that our approach can be combined
with a streaming algorithm to compute the barcode of the tower via matrix
reduction. The space complexity of the algorithm does not depend on the length
of the tower, but the maximal size of any subcomplex within the tower.
