How to use a water level<br>Use 50 to 100 feet (15 to 30 m) of tubing with a 5.16 in (13. 1 cm) diameter. A water level is easy to make at home with plastic tubing and a few other supplies. If you plan to level items that are a far distance from each other, you may opt for a longer tube.
A water level requires at least 7 different supplies 
The statement specifies that a long tube and a "few other supplies" are needed to make a water level, however it does not specify the exact number of supplies. It could be 7 items or a different number
( z1 require :ARG0 ( z2 level :mod ( z3 water ) ) :ARG1 ( z4 supply :ARG1-of ( z5 differ ) :quant ( z6 at-least :op 7 ) ) )