For a thorough discussion of the challenges and benefits of Design for All in the context of ICT today, see also the EDeAN White Paper (2005) and the "Report on the impact of technological developments on eAccessibility" of the DfA@eInclusion project.
Število 5 je na primer pitagorejsko praštevilo – formula_2 je hipotenuza pravokotnega trikotnika s stranicama 2 in 1, 5 pa je hipotenuza pravokotnega trikotnika s stranicama 3 in 4.