http://www.perlmonks.org?node_id=760916

No digits, no backslashes, no dollar signs, no quotes...
s bbq oprint q cs c and print grep !m w[a|c]w, a..c, a..c and print q +rq r and print grep m r[^np]r, n..p and print and print grep m i[^np] +i, n..p and print grep !m y[a|c]y, a..c and print q re and r and prin +tobe and print q cs c and print grep !m w[a|c]w, a..c, a..c and print + q rq r and print grep m r[^np]r, n..p and print and print grep m i[^ +np]i, n..p and print grep !m y[a|c]y, a..c and print q re and r and p +rint
I wonder is it possible to get rid of square brackets, pipes and '^'?

Update: Yes, it is possible!
Update2: use ellipses and reformat the code

s bbq oprint q as a and print grep! m aca, grep! m cac, a... c, a... c and print q aq a and print grep! m pnp, grep! m npn, n... p and print and print grep! m pnp, grep! m npn, n... p and print grep! m cac, grep! m aca, a... c and print q qe and q and printobe and print q as a and print grep! m aca, grep! m cac, a... c, a... c and print q aq a and print grep! m pnp, grep! m npn, n... p and print and print grep! m pnp, grep! m npn, n... p and print grep! m cac, grep! m aca, a... c and print q qe and q and print