Method  1

1.  Find 9  8-12 inch  rushes, swizzle sticks  or  drinking  straws  and  4 small
     to  medium sized rubber  bands.

2.   Hold one of  the rushes/straws vertically.

3.   Fold  a  second  straw  in  half  horizontally over  and at a  right  angle over the center of  to the  first straw with the second  straw projecting to the right.
      Snug the inside of  the bend  right  up to the first straw  at its  center.

4.   Grasp the center overlap tightly between thumb and fore-finger.

5.   Turn the two straws held together 90  degrees counter clockwise  (left) 
      (the two ends of the second straw will be projecting  upwards.)

6.   Fold the third straw in half over both parts of the second straw horizontally
      from left to right and  snug the inside of the fold up against the center
      and the second straw. Hold tight.

7.   Holding the  center  tightly!   Rotate all straws  (the entire assembly) 90
      degrees    counter clockwise. (left)

8.   This time  the bottom half of the first straw will be projecting upward.
      Fold a new straw in half over and across all straws projecting upward.

9.   Snug the straw tightly against the center and against the vertical straws.

10. Holding the center tightly rotate all straws (the entire assembly) 90 degrees Counter clockwise.

11. Fold a new  straw in half  over all vertical straws from left to right and
      snug up to center and to the right.

12. Repeat the process of rotating  all straws (the entire assembly) 90 degrees to the left and folding  the new straw  over until all straws  have been used.          Remember: Hold tight to the center.

13. When the last straw has been used snug all straws to center being careful to hold tight to the last straw folded.

14. Secure the last arm of the cross with a rubber band or if using rushes , platted straw or string.  Then secure each  other arm.

15. You may paint the drinking straws but be careful as wet paint will dissolve the thin paper covering.
Place rushes on a  flat surface to dry. You may wish to seal the rushes  when dry with a paint of your choice.

Method  2
This method produces a cross in a form which is much like the Eye of God and as such it brings to mind the antiquity of the Celtic Traditions of Ireland.
Materials:Two sticks and either rushes or wire or paper twist. Heavy gauge electrical wire (I use green!) makes for a great re-usable cross which can be re-constructed for each session.I start the cross and pass it through the class audience for completion.

1.Secure two sticks together at right angles.
    (I use string or tape).

2.Pull rush or wire from center attachment 
under the X in the top image over the top across the center to the left. Then under the bottom left
spoke then over the upper left spoke then curve back under it and continue in a clockwise direction (to the right). Ideally there should be a few inches of stick remaining exposed on each spoke.
It should resemble a cross more than an eye of god...

Method  3

This method produces a cross much like that of Method 1

For some reason this method seems to  be 
more Archaic than method 1. 

1.Tie nine straws together at their ends. 

2.Spread them as shown with the tied end  facing down (three to the right and two each other direction. (Image #1) 

3.Fold the front straw of the three under the other two.(Image2) 

4.Bring it up and over to be alongside the two at the nest corner.(Image3) 

5.Completed cross is shown in Image 4 

(Source: Joan Rendell, Your Book of Corn Dollies.)