5 Available from user levels and usable in the level editor
Trivia[]
If entering a form portal corresponding to the icon's current form and the portal is of a higher or lower position to the previous portal, the grid will vertically shift to realign with the new portal, with the exception of the cube and robot portals which do not lock the grid. This is demonstrated only once in a main level, Stereo Madness, with the alternate route for the third secret coin.
Until Fingerdash was released, main levels always featured all previously released forms.
Years, Space Pirates and Embers are the only main levels in all of Geometry Dash to omit the cube form, nor start with it.
Until Update 1.4, the ship only used the selected primary colour with slight shading. This can still be observed from the images in the How to play section of the Settings menu.
The ship and UFO each carry a slightly shrunken version of the selected cube design.
Under the Options section of the Settings menu, the cube and ball can be configured to each use an alternate mini icon design that substitutes the Icon Kit selection, and are not displayed in the Icon Kit. While the ship and UFO are under the effects of the size portal, they also display the cube's alternative mini design. Prior to Update 2.0, this was the default and only configuration.
Mathematically, the wave's movement can be mapped as:
Regular: slope = ±1 / ±45°
Mini: slope = ±2 / ~±63.435°
Due to naturally unchanging momentum, the wave does not respond to jump pads or rings, while gravity pads and rings flip gravity on contact without further effect on momentum.
Similar to other decorative level elements that pulsate to the music, the wave's trail will also pulsate to the music in Normal mode.
The robot portal is the only form portal that does not share their colours with a manipulation portal.
Entering form portals triggers a brief coloured inward pulse to occur as the icon passes through:
The cube portal lacks this effect.
The ship portal has a purple flash.
The ball portal has a red flash.
The UFO portal has a yellow flash.
The wave portal has a yellow flash and thin icon-primary-coloured outward pulse.
The robot portal has a red flash.
The spider portal has a red flash.
The swing portal has a yellow flash.
Prior to its formal introduction, the deactivation gravity portal is encountered in Back On Track and Polargeist as part of collecting secret coins, being implemented in Update 1.6.
The size portal is the only manipulation portal that neither its activation nor deactivation variant uses the colour blue.
While under the effects of the dual portal, a crash with either icon will terminate the other, although they cannot collide with each other.
While under the effects of the dual portal, the grid is locked to 9 vertical units, unless at least one of the forms is a ship, a UFO, a swing, or a wave, where the grid is then locked to 10 vertical units.
While under the effects of the dual portal, it is apparent that the intended gameplay will be counteracted if both icons of identical form acquire the same direction of gravity, causing an overlap and rendering only one icon for interaction. For this reason, in any case of dual icons of the same form, should one trigger a flip of gravity, both icons will have their gravity flipped to remain at inverted vertical positions. However, both balls and both spiders under the effects of the dual portal have independent gravity states so are not bound to inverted vertical positions. Moreover, the overlap issue is mitigated with an additional mechanic that if both balls are brought into the same direction of gravity, as the oncoming ball makes direct contact with the initial ball, the latter will emit an outward pulse and will reinvert the gravity of the oncoming ball automatically. Although the spider is also subject to the overlap issue, this mechanic as implemented for the ball is absent, allowing both spiders to overlap, nullifying the dual mechanic.
The colours of the teleportation portals are a reference to the game series Portal, with blue being the entry portal colour and orange being the exit portal colour.
Using teleportation portals that exit outside of the grid will result in the icon being returned beside the nearest boundary with no realignment of the grid. This does not occur for the cube or robot since they are not limited by a ceiling.
Entering manipulation portals triggers additional visual cues with colours matching the active portal:
The gravity portal triggers brief coloured lines moving in the direction of the gravity.
The mirror portal triggers every object to move horizontally towards the opposite side of the screen.
The size portal triggers a bolt of coloured lightning striking the icon along with the screen flashing twice, referencing the lightning bolt in the Super Mario Kart series.
The speed portal triggers coloured particles moving against the direction of the icon for a short time.
The teleportation portal triggers a bolt of lightning between the two portals along with the screen flashing briefly.
The name of the Swing form may come from the 2014 game Swing Copters. The mechanics of the Swing and the game share many similarities, with the main difference of the Swing Copters player moving left and right compared to the Swing's movement up and down.