hear them wrangle, every one defending his own for the best. "What? You keep not time in your proportions." "You sing them false. What proportion is this?" "Sesquipaltry." "Nay, you sing you know not what; it would seem you came lately from a barber's shop where you had 'Gregory Walker' or a Curranta played in the new Proportions by them lately found out, called 'Sesquiblinda' and 'Sesquihearkenafter'." Plaine and Easie Introduction to Practicall Musicke (1597) In general though, a slash or the numeral 2 shows a doubling of tempo, and paired numbers (either side by side or one atop another) show ratios instead of beats per measure over note value: in early music contexts for example is unrelated to 'third-notes'. A few common signs are shown: tempus imperfectum diminutum, 1:2 proportion (twice as fast); tempus perfectum diminutum, 1:2 proportion (twice as fast); or proportio tripla, 1:3 proportion (three times as fast, similar to triplets). In particular, when the sign was encountered, the tactus (beat) changed from the usual whole note (semibreve) to the double whole note (breve), a circumstance called alla breve. This term has been sustained to the present day, and though now it means the beat is a half note (minim), in contradiction to the literal meaning of the phrase, it still indicates that the tactus has changed from a short to a doubled value. Certain composers delighted in creating mensuration canons, "puzzle" compositions that were intentionally difficult to decipher. Irregular bar Irregular bars are a change in time signature normally for only one bar. Such a bar is most often a bar of 3/4, 5/4 or 2/4 in a 4/4 composition, or a bar of 4/4 in a 3/4 composition, or a bar of 5/8 in a 6/8 composition. If a song is entirely in 4/4 a change to 3/4 will make the song feel like it has skipped a beat, the opposite is true for 5/4 where it feels like the song adds a beat. If a song changes to 2/4 is will make it feel like that bar is half as long as all the others Some popular examples include "Golden Brown" by The Stranglers (4/4 in a 3/4 composition), "I Love Rock 'n' Roll" originally by the Arrows (3/4 in a 4/4 composition), "Hey Ya!" by Outkast (2/4 in a 4/4 composition), and "Wuthering Heights" by Kate Bush (different kinds of irregular bars in