A communication terminal for communicative connection to at least one other communication terminal via a network includes a receiving part configured to receive stroke data transmitted from the other communication terminal, an obtaining part configured to obtain name information that is associated with a transmission source of the stroke data under management by a management system on the network, and a display control part configured to perform control that displays an image based on the stroke data and an image based on the obtained name information in association with each other.

An image forming optical system (100) includes a first image forming unit (101) configured to form an image of a first surface (1) onto a second surface (2), a second image forming unit (102) including at least a portion of the first image forming unit (101) and configured to form an image of the second surface (2) onto a third surface (3), and a deflection unit (104) configured to deflect light from the second surface (2) toward the third surface (3). The numerical aperture of the first image forming unit (102) on the side toward the second surface (2) is larger than the numerical aperture of the second image forming unit (102) on the side toward the second surface (2).

A communication terminal for communicative connection to at least one other communication terminal via a network includes a receiving part configured to receive stroke data transmitted from the other communication terminal, an obtaining part configured to obtain name information that is associated with a transmission source of the stroke data under management by a management system on the network, and a display control part configured to perform control that displays an image based on the stroke data and an image based on the obtained name information in association with each other.