"Greg, sketch out an easy one from the math.

problems we have to dig into at West Point.

Give 'em something light from conic sections first." Cadet Holmes sketched out, on the back of an envelope, the demonstration of a short problem.
Tom and Harry looked on laughingly, at first.

Then their eyes began to open.
"Do you really have to dig up that sort of stuff at West Point," demanded Reade.
"Yes," nodded Dick.

"And now I'll show you another easy one, belonging to descriptive geometry." The two young engineers looked on and listened for a few moments.
"Stop!" commanded Hazelton, at last.