My 4th grade daughter came home with an extra credit question last week - to name the פרשיות that share a common שורש. This is a particularly fun exercise (for those who find this kind of thing fun) because you start out thinking it won't be so many but in the end, there are a lot. Here's what I found:
לך לך
וילך
וירא
וארא
ראה
חיי שרה
ויחי
ויצא
כי תצא
וישלח
בשלח
שלח לך
בא
כי תבא
משפטים
שופטים
תצוה
צו
כי תשא
נשא
בחוקתי
חוקת
Some statistics: two instance of a group of three, only one pairing that appears within the same ספר.
Did I miss any? Is there a case to be made that במדבר and דברים share commonality?