In the ruined temples of Central America, windows in the shape of upright and reversed taus also occur. The following series of architectural openings (fig. 39) are copied from Mr. Alfred P. Maudslay’s invaluable and splendid work, which has not, as yet, met with the recognition it so richly deserves.(16) They display besides the tau-shape (_g_ and _h_) other forms, the symbolism of which has been discussed. There are cross-shaped (_e_), square, round and oval windows (_d_, _j_, _b_ and _i_), the square obviously symbolical of the Earth and the round of the Heaven. Besides these there are openings in the form of a truncated cone (_a_ and _c_) and others ending in a narrow point (_k_). A striking form which recalls the Moorish arch and is shown in _f_, may, perhaps, be looked upon as an attempt to express the idea of a union of the Above and Below. [Illustration.] Figure 39. In connection with these architectural features it is interesting to study their names in the native languages. The Nahuatl names for windows are singularly expressive of their uses: tlachialoyan=the watching place or look-out; puchquiauatl=the smoke opening; tlanexillotl=a word which literally means light and splendor, and to which the following words are related: tlanextia, verb=to shine, shed light and radiance; tlanextilla=something revealed, made manifest, found or discovered, newly invented or formed (brought to light); tlanexcayotiliztli=figure, signification or example; tlanexcayotilli=something figured or significative. The meaning of the Maya name for window, ciznebna, is not clear, whilst that for door, chi, is the same as for mouth, opening or entrance. At the same time it is evident that, as in Mexico and elsewhere, the window openings in the Maya temples must have been associated with the idea of light, and the symbolical forms given to these besides their positions lead to the inference that they were actually regarded as mystic framed images, so to speak, of the supreme, invisible deity, through which, the light of day and the darkness of night alternately revealed themselves to those inside the sacred buildings. A careful study of the positions and orientations of these openings may yet prove that they also served for astronomical observation. The walls being usually pierced above reach, nothing but the sky could have been watched through them. But besides these, the interiors of Maya ruins contain interesting examples of mural openings and recesses which seem to have been carefully planned so that they should appear dark even in daytime and, in more than one case, these display the form of the upright tau, the symbol of darkness and the Below.(17) [Illustration.] Figure 40.