platelet count determination of the total number of platelets per cubic millimeter of blood; the direct platelet count simply counts the cells using a microscope, and the indirect platelet count determines the ratio of platelets to erythrocytes on a peripheral blood smear and computes the number of platelets from the erythrocyte count.
The modern spinner device is a decorative kinetic attachment to the wheel of an automobile. The spinner covers the center of a car's wheel and is designed to independently rotate by using one or more roller bearings to isolate the spinner from the wheel, enabling it to turn while the wheel is at rest.
Spinners ( a small pin in the center of a domino) were actually designed to hold the two domino materials (often ebony and ivory), together. It attached the white ivory face to the dark ebony side of the domino. It turned out the spinner had other great features besides just holding the dominoes in place.