Address: POLAND, Instytut Matematyki UW, ul. Banacha 2, 02-097 Warszawa, tel. +48 22 5544402 All texts were translated from Polish by Wiktor Bartol, bartol@mimuw.edu.pl. Delta no. 1   Some important questions about us and the world   Do dragons exist?, by Grzegorz Białkowski   Tetrahedrons and spheres, by Jerzy Bednarczuk   Exploring the Mars, by Marek Demiański   Refuting the laws of physics, by Jan Gaj   Cosmic harmony and Titius and Bode's law, by Tomasz Kwast   A forest laboratory, by Mme Pipsztycka   On powers of 2, by Pawel Strzelecki   How does a garden hose swell up, by Andrzej Szymacha   How to compute it?   Our readers propose Delta no. 2   An elementary problem   Refuting the laws of physics (II), by Jan Gaj   Home laboratory, by Janusz Gasiński   Desktop heavenly discoveries, by Jozef Smak   Two opinions on the infinity, by Jan Kalinowski and Pawel Strzelecki   The Scottish Book, by Marek Kordos   Our readers propose Delta no. 3   Calculus, Dedekind, and Cantor (A three-act play with prologue and epilogue)   On astronomical distances   Better than Archimedes   When two conservation laws come into conflict   Cans in boxes   Devil's arithmetic, or a contribution to angelology   Glass tears   A huge magic square   Points and slats   The equation of the watch   Why? Delta no. 4   Introduction: On what is not   The blackbody   The warmth   Does elementary charge exist?   The canals on Mars   Coronium and nebulum   The greatest prime number   The planet Vulcan   The material point   Trapped satelites   The celestial sphere   Formulas for the roots of polynomials of 5th degree   A rootless polynomial   On some sets which are not   Why is there no decent multiplication in 3-D space?   The aether   Monkey's saddle   Faster than light? Delta no. 5   Pál Erdös (1913 - 1996)   Force of a set   A short history of the proof of an interesting   Common Solution Sets of Real Polynomials   More on the European Union Contest for Young Scientists   Think and solve! Delta no. 6   Euler's characteristic, or combing one's hair   Map colouring   Euler's characteristic can be an equation   Rigid polygons, movable polygons and other polygons   On the possible forms of our space   Think and solve!   The little delta Delta no. 7   Introduction   About making coffee   How to check a processor   Shapes from shading   How to determine the distance from the Sun at the dead of night   Upwards-flowing water   DNA computing   Think and solve!   On the semantics of programming languages   Taking decisions   Needle Delta no. 8   The end of the world by Tomasz Chlebowski   Are real numbers real? by Roman Sikorski   Three solutions for 101 numbers by Aleksander Pełczyński Delta no. 9   An adventure in phisics by Marian Danysz   Time reversed by Michał Gawlikowski Delta no. 10   The Sun Eclipse