The Blue against the strip of black (thickness is also considered) and against white would produce different dimension. Red against white and blue with a border of black would have different dimensional effect. There by it is proved that the eyes may read different elasticity effect because of the contrast of colors.

Bellow are examples of a few common illusion that human beings experience-

Fig. 2 A	Fig. B

In Fig. 2 A both the arrows (X & Y) are of the same length. However the ‘X’ seems longer than ‘Y’. In the Fig. 2 B all the three parallel lines- a, b & c are of the same length. However, it appears ‘a’ is longer compared to ‘b’ and ‘c’. Therefore, it seems we cannot trust our own eyes. Artist and design have utilized the deficiency of human eyes and applied in their creative work to achieve certain effect.

Following are further more examples that are popularly shown to illustrate human illusionistic views-

Fig. 3A	Fig. 3B
Fig. 4 A	Fig. 4 B

Height-Width Illusion- an upright line segment appears longer nearby equal horizontal line segments (Fig 4. A)
Illusion of Contour- An open or empty figure appears to have greater area or capacity than an equal closed or filled figure (Fig. 4. B).

Fig. 5 A Illusion in Depth (Ant’s Eye View/ Bird’s Eye View)	Fig. B. Illusion in Color Contrast (Primary- Secondary Color)	Fig. C Illusion flat & convex surface

Source; http://www.google.co.in/search?hl=en&q=illusion&bav=on.2,or.r_gc.r_pw.,cf.osb&biw=1272&bih=577&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=b3fAT42OB4OurAegpMzpCQ ; May 26, 2012