Instructions:

Move the pouring tube around with the mouse and pour concrete by clicking LMB

Use 'a' and 'd' to move the left formwork sideways and 'w' and 's' vertically

Use 'f' and 'h' to move the right formwork sideways and 't' and 'g' vertically

Don't pour too much concrete in too fast or the pressure will cause the concrete to break out of the formwork