qdpllexp_[12].qdimacs are baby examples.
qdpllexp_2[012].qdimacs  double the solving time for each increment
on some QBF solvers, but the size grows by 16 literals and 5 variables
and 4 clauses for each increment.

These formulas are simplified versions of those reported in
a workshop paper (submitted).

qdpll-exponential.csh and qdpll-exponential.awksh provide a generator
for examples.  Read the comments in the scripts.