I believe this is the start of a traditional origami Frog model which is where this base gets its name.

Frog Base Step 1

1) Start off by folding a Square Base.

 

Frog Base Step 2

2) Looking at the base from the top you’ll notice that there are four sort of arms.

 

Frog Base Step 3

3) We’re going to do a squash fold on each of these arms. Pick one…

 

Frog Base Step 4

4) …and squash fold it.

 

Frog Base Step 4

5) Flip the model over and squash fold the opposite flap.

 

Frog Base Step 5

6) There are two more flaps on the left and the right, pick one and squash fold it.

 

Frog Base Step 6

7) Once you’ve squash folded each of the flaps then you have the Frog Base.

 

Frog Base Step 7

8) If you open the model up you’ll notice these Mountain (black) and Valley (red) folds.

 

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