Issaouane Erg confined to basins. Sand in the Issaouane Erg, below the level of the sand dunes, has accumulated to a depth of 20 to 30 meters. It has barchan dunes as well as star dunes of 300 to 430 meters high. The presence of both barchan dunes (which form due to unidirectional winds) and star dunes (which form when winds from various directions deposit sand) "suggests that wind regimes have changed over time". NASA's "Earth Observatory" notes all three types of erg dunes are present in the photos of the Issaouane Erg taken from the International Space Station: stationary mega dunes,
What Love Is Made Of does best, albeit slightly more polished around the edges". He finally wrote that "the result is more than enough to keep our obsession rolling through yet another summer stretch". Sam Lansky from Idolator believed that the song had potential to become a "club hit" and named it the "biggest thing she’s recorded to date", while like other critics, highlighting Katy's vocals. Commercially, "What Love Is Made Of" fared well on European charts. It stayed two weeks at the UK Singles Chart, where it peaked at number 21. On its component chart, the UK Dance chart, its peak was higher, at