strengthen and extend examples for PR#7152
strengthen and extend examples for PR#7152

yunxing/ocaml,msprotz/ocaml,msprotz/ocaml,gerdstolpmann/ocaml,msprotz/ocaml,yunxing/ocaml,gerdstolpmann/ocaml,msprotz/ocaml,gerdstolpmann/ocaml,gerdstolpmann/ocaml,yunxing/ocaml,yunxing/ocaml,msprotz/ocaml,gerdstolpmann/ocaml,yunxing/ocaml