Topologic is a simple renderer for certain higher-dimensional geometric primitives and some regular 3D shapes. The idea is to make it easy for students of certain higher-dimensional maths and physics topics to visualize the typical primitives in those fields and get a grasp for the topic. Note: the program as such is freeware, while the part of it that deals with the Mathematics to project the geometric shapes to 3-space and 2-space has been released separately under an MIT/X style license.
lib4d_sql is a C library that provides the required functions (connect, prepare, execute, etc.) for writing an SQL client for 4D databases. It uses the public 4D SQL protocol, which is supported by 4D products since version 11. It is already used by the PDO_4D Open Source project, and it might be used to provide others drivers for JDBC, ADO, or ActiveRecord.