==Types of pseudo 3D==
The global term is parallel projection. But in common language we often talk indistinctly about Isometric...
Used parellel projections There are often actually 2 families :symmetric and asymmetric parallel projections.
*Symmetric : the X and Z axis form an equal same angle with Y axis. *Asymmetric : X and Z axis form different angles with Y axis. Used parallel projections are often : *'''"Horizontal " Oblique projection :''' [[Pac-Mania]] obviously, yet "Beat Them Up" games (like Double dragon or Renegade) or even few "Shoot them Up"s (Mag Max) do use some kind of this.
**In those case, we can talk about '''Perspective Cavalière (F) / Kavalierperspektive (D) / Perspectiva caballera (E)''' (is there en English equivalent) which is a perspective with unchanged 2D vertical and horizontal and a 3rd Axis in oblique. This specific projection enable to keep the 2D gameplay based on vertical and horizontal movement.
*'''Isometric projection :''' [[Head Over Heels]] is the most well known.
*'''Oblique 135°/135°/92° projection pseudo isometric :'''It is some sort of those are symmetric parallel projections with angles for the X and Z axis which suit the Pixel ratios, hence producing harmonius and regularly shaped lines. Some "Mode1 " isometric. In this, X and Z having 45µ° angle with Y. the diagonal ratio for the diagonal grid is 1 X1 for 1Y1. This was sometimes used in some Speccy originated games as this enable to put more tiles or elements on the horizontally limited Speccy resolution .
**Example : '''W*H*B''', a modern Bloxorz' Clone on ZXSpectrum.
**A More CPC oriented example game is probably '''Frontiers''' (Zafiro Software (1988)).
on the other hand you can also flatten this with a 4x1 ratio, more often seen on CPC (and in Mode0).
1x1 or 4x1 are way to reduced the needed screen dimension to display the same number of elements...
*1x1 is better for horizontally limited display.
*4x1 is better for vertically limitade display.
==Masked Sprites and Elements==