How to make transparent rectangles?

Solar2D Advanced Graphics
#1

is there any way to make transparent squares like the one attached? Transparent in the middle but then have a solid stroke?

#2 
local dispCX = display.contentCenterX local dispCY = display.contentCenterY local rect1 = display.newRect(dispCX,dispCY,100,50) rect1:setFillColor(0,0,0,0) rect1.strokeWidth = 6 rect1:setStrokeColor(0)
#3

Thanks Alex! I didn’t realize that setFillColor had a 4th argument for alpha.  

#4 
local dispCX = display.contentCenterX local dispCY = display.contentCenterY local rect1 = display.newRect(dispCX,dispCY,100,50) rect1:setFillColor(0,0,0,0) rect1.strokeWidth = 6 rect1:setStrokeColor(0)
#5

Thanks Alex! I didn’t realize that setFillColor had a 4th argument for alpha.