What are all the structural isomers of a tertiary amine with the sum formula C6H15N? According to the solutions there exist 7 different structural isomers 'containing 3 degree amines' for the molecular formula  $\ce{C_6H_{15}N}$

I tried and made a few, here are those 



I have been trying since an hour and all I made were the repetitions of these 5 only. Could anyone suggest me the remaining 2?
Please note that this is just a visualization of the comment given by LDC3!

Here are the two missing isomers: