With the advent of computers, these devices have become unpractical attachments. So people no longer use a practical way to create a sample. When people use the computer to print, the printer can check the effect of his playing with a monitor or plotter.
Single-ended machines are often used to proofread multiple-ended machines without using a computer, but it is impossible to produce precise samples with the same wire. 2.5-yard or larger proofing machines do exist to verify the information stored in the tape and make samples for customers to see, but they are very expensive, and most embroidery vendors use their machines to provide accurate samples for customers.