Your answer should be based around diagram$($s$)$ but they may include some supporting maths.

Consider a situation in which the vectors $f$ and $g$ have strictly positive components:

$f_1,f_2,g_1,g_2>0.$ Show that it can be optimal for the principal to offer a contract$/$job in which one of the tasks $e_1$ or $e_2$ is blocked $($forced to zero$).$ We are thinking here that effort levels are still non contractible but it is possible to detect if any of a task is undertaken, or there is some way to modify the workplace to prohibit that task.

What is a real world example of these kinds of multitask problems? Explain your answer and offer solutions as appropriate.