Top Design with Filter FactoryGradients with trigonometric function 
In brief, sequential changes of numbers result gradients when treated as pixel values. Because the trigonometric functions return periodical change of numbers, we can also create gradients with these functions as sin(), cos() or tan()...  
Sine curveThe trigonometric functions of Filter Factory return values from 1024 to 1024 on Mac. They return different values, 512 to 512 on PC, so PC users need to put 512 instead of 1024 in the description below. Sin(x) varies between 1024 and 1024. It's too wide for pixel values, and without any corrections, most part of the image will be black or white out. 

Wavy boardWith the scl() function, we can reduce the values that the sin() returns to the scope of pixel values, and wavy board appeares. To control frequency of the wave with a slider control, x*ctl(0) is used instead of x. 

PipesApplying the abs() function, we can get the image covered with pipe. The function returns absolute value, so abs(sin(x)) returns 0 to 1024, not 1024 to 1024. 