In color theory, a purple is defined as any non-spectral color between violet and red (excluding violet and red themselves). The spectral colors violet and indigo are not purples according to color theory, but they are purples according to common English usage since they are between red and blue.
Apex Learning was started in 1997 by Microsoft co-founder Paul Allen on the idea that online courses and test prep, which were already succeeding in higher education, could be applied to K-12.
History [edit]. Initially described as âFour Stages for Learning Any New Skillâ, the theory was developed at Gordon Training International by its employee Noel Burch in the 1970s. It has since been frequently attributed to Abraham Maslow, although the model does not appear in his major works.