He used trompe-l'oeil to create an eight meter long gallery which appears thirty seven meters long in the Palazzo Spada, and he added a concave volume to Girolamo Rainaldi's designs for the facade and two bell towers of the Sant'Agnese in Agone.  He was commissioned to create an oratory next to the Chiesa Nuova for the Fillipini order, as well as designing the oval staircase for the Palazzo Barberini. One of his works features cherubims with six wings and uses two superimposed equilateral triangles as the basis for six chapels and has a dome with a corkscrew lantern. Another work features a corrugated oval in an oval dome, and is marked by this man's typical attempts to create an effect of undulation in his buildings. For 10 points, name this Baroque achitect of the Sant'Ivo alla Sapienza and the San Carlo alle Quattro Fontane, a rival of
He used trompe-l'oeil to create an eight meter long gallery which appears thirty seven meters long in the Palazzo Spada, and he added a concave volume to Girolamo Rainaldi's designs for the facade and two bell towers of the Sant'Agnese in Agone.  He was commissioned to create an oratory next to the Chiesa Nuova for the Fillipini order, as well as designing the oval staircase for the Palazzo Barberini. One of his works features cherubims with six wings and uses two superimposed equilateral triangles as the basis for six chapels and has a dome with a corkscrew lantern. Another work features a corrugated oval in an oval dome, and is marked by this man's typical attempts to create an effect of undulation in his buildings. For 10 points, name this Baroque achitect of the Sant'Ivo alla Sapienza and the San Carlo alle Quattro Fontane, a rival of Gianlorenzo Bernini. 
He used trompe-l'oeil to create an eight meter long gallery which appears thirty seven meters long in the Palazzo Spada, and he added a concave volume to Girolamo Rainaldi's designs for the facade and two bell towers of the Sant'Agnese in Agone.  
{Francesco Borromini}