In 04/05, I single-handedly wrote a large Windows Mobile (.Net CF) and SOA platform for managing proof of delivery across 5000 devices which used server-push messaging over semi-persistent GPRS links. This required about 6 months of work after 3 months of R&D. It was delivered on time, with zero defects, worked perfectly on low bandwidth connections and required no training for the user (less than 5% of the userbase had problems using it with no training).

It was fast, even over low bandwidth connections. Virtually real time when a link was up.

It was beautiful because it was easy to use and abstracted the messaging system and connection availability entirely.

It was possible because it worked first time with no regressions or defects in the field reported in over 6 years. It had to work first time as there was no upgrade channel for the users.