(no subject)

[timelets]

Let's create a slice category constructed like this:

f1: iPhone1 -> iPhone
f2: iPhone 2 -> iPhone
...
fn: iPhone n -> iPhone

g1: f1 -> f2
g2: f2-> f3
...

Then, there should be a pullback category A, so that

f1': A -> iPhone1
f2': A -> iPhone2
...
fn': A -> iPhone n

What would it be?