,------------------+--------+--------+----------.
| Task             | Start  | End    | Duration |
+------------------+--------+--------+----------+
| Prototype design | Day 1  | Day 10 | 10 days  |
+------------------+--------+--------+----------+
| Code prototype   | Day 11 | Day 20 | 10 days  |
+------------------+--------+--------+----------+
| Write tests      | Day 11 | Day 15 | 5 days   |
`------------------+--------+--------+----------'