We start in Max by creating a box 16x16x6(I am using inches as units) in the front viewport

Set the segments to 4,4,2

Let's convert the box to Editable Poly

Select the 16 front facing polygons, right click and choose Convert to vertex.

You now will have 25 verts selected, deselect the middle 9 vertices so you have 16 remaining.

Move these verts along the Negative Y axis as shown.

Repeat the above steps for the rear facing verts only this time along the positive y axis.

Add a meshmooth modifier with 2 iterations, we will toggle this

to check our progress on the high poly model

The result can be seen in figure 1.

Select Edge sub-object level select the 2 edges shown in figure 2 at each of the pillow's

4 corners for a total of 8 edges.

Chamfer the edges(I used a value of .25)

Select 1 of the middle edges that divides the pillow (front to back) and hit alt+L to

select the entire loop.

Select the scale tool and uniformly scale the loop to 112%

Apply a Spherify Modifier with a value of 25 percent(below Meshsmooth in the stack)

Right click the spherify modifier, and select collapse to.

The result should match figure 3.

Select verts between the 4 pillow corners and move them accordingly to creates "Sags"

between the corners

Select the 2 verticle edges shown in figure 4. Hit alt+r to select the corresponding edge rings

Use Connect with a value of 1 to create 2 new loops around the pillow(figure 4)

Repeat the last steps only this time using the corresponding horizontal edge rings

This will create 2 vertical loops.

Resulting "Base" Pillow figure 5.

Select the 2 edges shown in figure 6, and chamfer them. I used a value of .32

Select the 3 edges shown in figure 6, and use Connect(value 1) for the result shown.

Select the 2 edges shown(fig7), and move them down alony the negative z axis as shown.

Select the 8 verts as illustrated(fig7), and move them along the positive x axis.

We do this to create a more natural wrinkle, if all the wrinkles went straight across the pillow

it wouldn't appear natural IMO.

Wrinkles usually appear 2 or more in an area, so lets make another wrinkle to repeat the

shape of the first.

To the left of the wrinkle we have just created, we are going to add a couple of edges.

Select the 3 edges shown(fig 8), use connect with a value of 2.

Move the left 2 edges(fig 8) toward the right 2 edges, then move them down along the

negative z axis.

Turn on your meshmooth modifier to see the results.

Select the edge shown, and use insert vertex from the edit edges menu.

Click on the mid point of the edge to insert a vertex.

Slect this veretex, and move it down along the neg z axis as shown.

Select the polygon shown

Inset with a value of .25

Activate your meshsmooth modifier to see the result.

Good luck, and have fun!