Delete the grouped rows indicated on the left.

Select the top and bottom rows and change the line weight to 1 point (in the Set Line Width drop down list). Change the outline color to the color shown.

Select the center two rows and change the line weight to 1 point and the outline fill color as shown.

TIP: To open the Outline Color Editor, click the color wheel icon, at the left of the screen palette, with the Right mouse button.

Blend-O-Rama!!!

Select the Blend Tool and drag from the top grouped row of squares to the top row (of the two middle rows). Change the Blend Steps to 10. The squares will slightly overlap. This is OK.

Now blend from the bottom row to the bottom of the middle two rows. Change the Blend Steps to 5.

Select all the blends. From Arrange menu, select Convert to Editable Shapes. This deactivates the Blends.