Define the features of E1 Mechanism ?

Can you help me understand the mechanism for this question? Please include all arrow pushing.

Propose a reasonable mechanism

What type of mechanism is needed for this?

The reaction between isocyanide 1 and ketone 2 occurs only after a base (t-BuOK) is added to a solution of the reactants in ethanol and CH2Cl2. The final product is nitrile 4, which is believed to arise from ethanolysis of intermediate 3 under the reaction conditions. Draw a plausible reaction mechanism to describe the formation of 4 from 1 and 2. Draw all intermediates and show all electron-pushing. You are not expected to know if your proposed mechanism is the actual mechanism supported by experimental evidence, but it must be reasonable, and the electron pushing should be correct. Hint: start by deprotonating 1 and forming the first bond, then label and map the atoms onto the intermediate. Ts Ts = ONS=O N=C= t-BuO K H -- EtOH, CH2Cl2 2 3 NEC

provide full reaction mechanisms