The smaller the slits, the sharper the pictures.
Uchatius in Vienna constructed an apparatus as early as 1853 to throw these pictures of the stroboscopic disks on the wall.

Horner followed with the daedaleum, in which the disk was replaced by a hollow cylinder which had the pictures on the inside and holes to watch them from without while the cylinder was in rotation.

From this was developed the popular toy which as the zooetrope or bioscope became familiar everywhere.

It was a revolving black cylinder with vertical slits, on the inside of which paper strips with pictures of moving objects in successive phases were placed.

The clowns sprang through the hoop and repeated this whole movement with every new revolution of the cylinder.
In more complex instruments three sets of slits were arranged above one another.