Ameoba. (One of the smallest and simplest of creatures)

I wrote this after reading the definition of ameoba in the dictionary.

I am an amoeba
I am so very small
Too small I often think
To even exist at all

Another on my shoulders
I am two amoeba tall
To all other amoeba
I am built like a brick wall

Another on his shoulders
I am feeling rather dim
I realise I cannot see
Half as far as him

With another on the top
I am squashed down flat
Experimenting ended
Now that's the end of that

I find it most annoying
In fact it gets my gall
I'm wider than the others
But nowhere near as tall