A method and apparatus are provided for forming high-yield tissue microarray blocks capable of producing 1,000 or more replicate slides. The circular memory structures may include rate wheels that include a group of sequentially arranged slots. A single detector is used to detect the lights emitted from the plurality of samples at these different times. Further still, the method includes generating a new code associated with a new predetermined currency value, and sending the new code to a sender of the defined payment amount. Each of the two end surfaces is circular arc-shaped, and the radius of each of the two end surfaces is in the range of 0.